Common Word Problems This handout is devoted to the reoccurring word problems that appear on the GMAT. Remember to continue Plugging in and Backsolving for problems that you cannot set up algebraically. Dirt Formula You may have to use the formula a couple times in one problem If a car travels at an average speed of 70 kilometers per hour for 4 hours, how many kilometers does it travel? On a 400-mile trip, car X traveled half the distance at 40 miles per hour and the other half at 50 miles per hour. What was the average speed of car X? Work 2 or 3 individuals who work at different rates Formula If machine X can produce 1,000 bolts in 4 hours and machine Y can produce 1,000 bolts in 5 hours, in how many hours can machines X and Y, working together at these constant rates, produce 1,000 bolts? 2 different size groups who work at the same rate Formula If 5 workers take an hour to dig a ditch, how long should it take 12 workers to dig a ditch of the same size? Proportion If 5 shirts cost $44, then at this rate, what is the cost of 8 shirts? Ratio Use the ratio box If ¾ of the employees in a supermarket are not college graduates, what is the ratio of the number of college graduates to those who are not college graduates? Last year, the ratio of the number of tennis matches that Central College’s women’s team won to the number of matches they lost was 7:3. What percent of their matches did the team win? There are 90 red and blue marbles in a bag in a ratio of 5:13 respectively. How many blue marbles are there? 1 Measurement Convert A train travels at a constant rate of 25 meters per second. How many kilometers does it travel in 5 minutes? (1 kilometer = 1,000 meters) Average Finding the average The temperature at noon in Coldtown, USA was 5F on Monday, 10F on Tuesday, -2F below zero on Wednesday, -5F below zero on Thursday, 0F on Friday, 4F on Saturday, and -1F below zero on Sunday. What was the average temperature at noon for the week? Finding the missing element Formula Sum of the numbers = Sum of average that many times If the average annual income of 10 workers is $15,665 and two of the workers each make $20,000 for the year, what is the average annual income of the remaining 8 workers? Mixture Formula If 6 pounds of nuts that cost $1.20 per pound are mixed with 2 pounds of nuts that cost $1.60 per pound, what is the cost per pound of the mixture? Percentage Regular Translate “Per” What is 45 percent of 7/12 of 240? Try __________ ___ to solve this type The price of an item is discounted by 20 percent and then this reduced price is discounted by an additional 30 percent. These two discounts are equal to an overall discount of what percent? “What was the percentage change?” Formula If the price of an item increases from $24 to $30, what is the percent increase in price? “What was the original amount?” Formula Try __________ to solve this type 2 A certain customer paid $24 for a dress. If that price represented a 25 percent discount on the original price of the dress, what was the original price of the dress? Interest Formula Simple vs. Compound You will often have to take the annual rate and divide among the year; semiannually, quarterly, or monthly If $8,000 is invested at 6 percent simple annual interest, how much interest is earned after 3 months? Profit Profit = _________ – __________ A certain appliance costs a merchant $30. At what price should the merchant sell the appliance in order to make a gross profit of 50 percent of the cost of the appliance? Venn Diagrams Remember the center must be subtracted from the two sets In a survey, 60% of those surveyed owned a car and 80% of those surveyed owned a TV. If 55% owned both a car and a TV, what percent of those surveyed owned a car or a TV or both? In a certain production lot, 40 percent of the toys are red and the remaining toys are green. Half of the toys are small and half are large. If 10 percent of the toys are red and small, and 40 toys are green and large, how many of the toys are red and large? Permutations Each time you have to make a choice, draw a space If there are 3 different roads from Syracuse to Binghamton and 4 different roads from Binghamton to Scranton, how many different routes are there from Syracuse to Scranton that go through Binghamton? A club has 20 members. They are electing a president and a vicepresident. How many different outcomes of the election are possible? (Assume the president and vice-president must be different members of the club.) 3 A train travels at an average speed of 50 miles per hour for 2 ½ hours and then travels at a speed of 70 miles per hour for 1 ½ hours. How far did the train travel in the entire 4 hours? A) 120 B) 185 C) 210 D) 230 E) 240 Pam and Sue drove to a business meeting 120 miles away in the same car. Pam drove to the meeting and Sue drove back along the same route. If Pam drove at 60 miles per hour and Sue drove at 50 miles per hour, how much longer, in minutes, did it take Sue to travel the distance than it did Pam? A) 4 B) 10 C) 20 D) 24 E) 30 A train travels at an average speed of 20 mph through urban areas, 50 mph through suburban areas, and 75 mph through rural areas. If a trip consists of traveling half an hour through urban areas, 3 ½ hours through suburban areas, and 3 hours through rural areas, what is the train’s average speed for the entire trip? A) 48 1/3 B) 50 C) 54 3/7 D) 58 4/7 E) 59 2/7 The distance from Cleveland to Buffalo is 200 miles. A train takes 3 ½ hours to go from Buffalo to Cleveland and 4 ½ hours to go back from Cleveland to Buffalo. What was the average speed of the train for the round trip from Buffalo to Cleveland and back? A) 25.39 B) 26 C) 49.5 D) 50 E) 50.79 A car is traveling on a straight highway. At 10 o’clock, it passes a truck traveling in the same direction. The truck continues on the highway traveling at 50 mph while the car travels at 65 mph. How far apart are the car and the truck at 2 o’clock? A) 15 miles B) 30 miles C) 60 miles D) 200 miles E) 260 miles Stan drove for h hours at a constant rate of r miles per hour. How many miles did he go during the final 20 minutes of his drive? A) 20r B) hr 3 C) 3hr D) hr E) 20 r 3 Two airplanes are 300 miles apart and flying directly toward each other. One is flying at 200 mph, and the other at 160mph. How long will it take for the two planes to meet? A) 36 minutes B) 50 minutes C) 1 hour and 12 minutes D) 1 hour and 40 minutes E) 1 hour and 41 minutes Doreen can wash her car in 15 minutes, while her younger brother Dave takes twice as long to do the same job. If they work together, how many minutes will the job take them? A) 5 B) 7 ½ C) 10 D) 22 ½ E) 30 If 15 workers can pave a certain number of driveways in 24 days, how many days will 40 workers take, working at the same rate, to do the same job? A) 9 B) 12 C) 20 D) 25 E) 64 4 If Paul can paint a fence in 2 hours and Fred can paint the same fence in 3 hours, Paul and Fred working together can paint the fence in how many hours? A) 5 B) 2 ½ C) 1 1/5 D) 1 E) 5/6 There are two taps, tap 1 and tap 2, in a keg. If both taps are opened, the keg is drained in 20 minutes. If tap 1 is closed and tap 2 is open, the keg will be drained in 30 minutes. If tap 2 is closed and tap 1 is open, how long will it take to drain the keg? 1 hour A) 10 minutes B) 40 minutes C) 45 minutes D) 50 minutes E) 60 minutes When both floodgates A and B are open, a reservoir drains in 3 1/3 days. If floodgate A alone drains the reservoir in 10 days, how many days does it take floodgate B alone to drain the reservoir? A) 4 B) 5 C) 6 2/3 D) 10 E) 12 A worker is digging a ditch. He gets 2 assistants who work 2/3 as fast as he does. If all 3 work on a ditch, they should finish it in what fraction of the time that the worker takes working alone? A) 3/7 B) 1/2 C) 3/4 D) 4/3 E) 7/3 Machine A and Machine B are each used to manufacture 660 sprockets. It takes machine A 10 hours longer to produce 660 sprockets than machine B. Machine B produces 10 percent more sprockets per hour than machine A. How many sprockets per hour does machine A produce? A) 6 B) 6.6 C) 60 D) 100 E) 110 If 4 boys can shovel a driveway in 2 hours, how many minutes will it take 5 boys to do the job? A) 60 B) 72 C) 96 D) 120 E) 150 If Sam can finish a job in 3 hours and Mark can finish a job in 12 hours, in how many hours could they finish the job if they worked on it together at their respective rates? A) 1 B) 2 2/5 C) 2 5/8 D) 3 ¼ E) 4 If Art and Rita can do a job in 4 hours when working together at their respective constant rates and Art can do the job alone in 6 hours, in how many hours can Rita do the job alone? A) 2 B) 8 C) 8 ½ D) 10 E) 12 A worker makes a basket in 2/3 of an hour. If the worker works for 7 ½ hours, how many baskets will he make? A) 5 B) 10 C) 11 ¼ D) 12 E) 15 If m is proportional to n and m = 5 when n = 4, what is the value of m when n = 18? A) 11 B) 14.4 C) 20 D) 22.5 E) 25 The concession stand at Cinema City sells popcorn in three sizes: large, super, and jumbo. One day, Cinema City sold 240 bags of popcorn, and the ratio of large to super to jumbo was 8:17:15. How many super bags of popcorn were sold that day? A) 48 B) 90 C) 102 D) 108 E) 120 5 If the ratio of juniors to seniors on a team is 3:5, what percent of the team members are seniors? A) 37.5% B) 40% C) 60% D) 62.5% E) It cannot be determined from the information given The average of 5, 10, 15, and z is 20. What is z? A) 0 B) 20 C) 25 D) 45 E) 50 The average of 10 numbers is –10. If the sum of 6 of them is 100, what is the average of the other 4? A) –100 B) –50 C) 0 D) 50 E) 100 Sheila took five chemistry tests during the semester and the average of her test scores was 85. If her average after the first three tests was 83, what was the average of her fourth and fifth tests? A) 83 B) 85 C) 87 D) 88 E) 90 How many liters of a solution that is 15 percent salt must be added to 5 liters of a solution that is 8 percent salt so that the resulting solution is 10 percent salt? A) 2 B) 6 C) 7 D) 10 E) 13 A solution is 90 percent glycerin. If there are 4 gallons of the solution, how much water, in gallons, must be added to make a 75-percent glycerin solution? A) 1.8 B) 1.4 C) 1.2 D) 1.0 E) 0.8 Amanda bought a $60 sweater on sale at 5% off. How much did she pay, including 5% sales tax? A) $54.15 B) $57.00 C) $57.75 D) $59.85 E) $60.00 A coat was sold for $75. The coat was sold for 150% of the cost of the coat. How much did the coat cost? A) $11.25 B) $50.00 C) $63.75 D) $112.50 E) $225.00 What was the percentage discount on a which originally cost $5,000 was reduced to $4,800? A) 200% B) 96% C) 40% D) 4.16% E) 4% If 25% of 260 equals 6.5% of a, what is a? A) 10 B) 65 C) 100 D) 130 E) 1000 From 1989 to 1990, the number of applicants to a college increased 15% to 5060? How many applicants were there in 1989? A) 759 B) 4301 C) 4400 D) 5819 E) 5953 During his second week on the job, Mario earned $110. This represented a 25% increase over his earnings of the previous week. How much did he earn during his first week of work? A) $82.50 B) $85.00 C) $88.00 D) $137.50 E) $146.67 6 A Merchant was selling an item at a certain price, then marked it down 20% for a spring sale. During the summer, he marked the item down another 20% from its spring price. If the item sold at the summer price, what percent of the original price did it sell for? A) 40% B) 60% C) 64% D) 67% E) 80% From 1994 to 1995 the sales of a book decreased by 80%. If the sales in 1996 were the same as in 1994, by what percent did they increase from 1995 to 1996? A) 80 B) 100 C) 120 D) 400 E) 500 If x% of y is 10, what is y? A) 10 x B) 100 x C) 1000 D) E) x x 100 x 10 Ms. Lopez deposits $100 in an account that pays 20% interest, compounded semiannually. How much money will there be in the account at the end of one year? A) $118.00 B) $120.00 C) $121.00 D) $122.00 E) $140.00 How much interest will $10,000 earn in 9 months at an annual rate of 6%? A) $450 B) $540 C) $560 D) $600 E) $667 What will $1000 be worth after three years if it earns interest at the rate of 5% compounded annually? A) $1,150 B) $1,155 C) $1,157.63 D) $1,158.52 E) $1,160 If $10,000 is invested at 10 percent annual interest, compounded semiannually, what is the balance after 1 year? A) $10,010 B) $10,015 C) $11,000 D) $11,025 E) $12,100 Half the graduating class of a college was accepted by a business school. One-third of the class was accepted by a law school. If one-fifth of the class was accepted to both types of school, what fraction of the class was accepted only by a law school. A) 1/60 B) 2/15 C) 1/3 D) 1/2 E) 4/5 At a school of 50 students, 20 students are enrolled in history and 12 are enrolled in mathematics. If 8 are enrolled in both classes, how many are enrolled in neither? A) 10 B) 18 C) 24 D) 26 E) 40 In a certain town 40% of the people have brown hair, 25% have brown eyes, and 10% have both brown hair and brown eyes. What percentage of the people in the town have neither brown hair nor brown eyes? A) 35 B) 40 C) 45 D) 50 E) 55 7 7 basketball teams play in a league against each other. At the end of the season, how many different ways could the top 3 teams end up in the rankings? A) 6 B) 42 C) 210 D) 5,040 E) 5,045 At a restaurant, you must choose an appetizer, a main course, and a dessert. If there are 2 possible appetizers, 3 possible main courses, and 5 possible desserts, how many different meals could you order? A) 60 B) 30 C) 10 D) 6 E) 3 8