Questions #1 – 5 from http://www.purplemath.com/modules/mixture.htm
1. Suppose you work in a lab. You need a 15% acid solution for a certain test, but your supplier only
ships a 10% solution and a 30% solution. Rather than pay the hefty surcharge to have the supplier
make a 15% solution, you decide to mix 10% solution with 30% solution, to make your own 15%
solution. You need 10 liters of the 15% acid solution. How many liters of 10% solution and 30%
solution should you use?
a. Answer: 2.5 liters of the 30% solution, 7.5 liters of the 10% solution
2. How many liters of a 70% alcohol solution must be added to 50 liters of a 40% alcohol solution to
produce a 50% alcohol solution?
a. Answer: 25 liters of 70% alcohol
3. How many ounces of pure water must be added to 50 ounces of a 15% saline solution to make a
saline solution that is 10% salt?
a. Answer: 25 ounces of water
4. Find the selling price per pound of a coffee mixture made from 8 pounds of coffee that sells for
$9.20 per pound and 12 pounds of coffee that costs $5.50 per pound.
a. Answer: $6.98/pound
5. How many pounds of lima beans that cost $0.90 per pound must be mixed with 16 pounds of corn
that costs $0.50 per pound to make a mixture of vegetables that costs $0.65 per pound?
a. Answer: 9.6 pounds of lima beans
Questions # 6-8 are from http://www.purplemath.com/modules/quadprob.htm
6. An object is launched at 19.6 meters per second (m/s) from a 58.8-meter tall platform. The
equation for the object's height s at time t seconds after launch is s(t) = –4.9t2 + 19.6t + 58.8,
where s is in meters. When does the object strike the ground?
a. Answer:The object hits the ground 6 seconds after launch.
7. An object in launched directly upward at 64 feet per second (ft/s) from a platform 80 feet high.
What will be the object's maximum height? When will it attain this height? The equation to
represent the object’s movement is s(t) = –16t2 + 64t + 80.
a. Answer: The object will be at its maximum height at 2 seconds and will be 144 feet high.
**This is a good calculator graphing question – find the maximum!
8. An object is launched from ground level directly upward at 39.2 m/s. For how long is the object at
or above a height of 34.3 meters? The equation to represent the object’s movement is s(t) = –
4.9t2 + 39.2t
a. The object is at or above 34.3 meters for six seconds.
http://www.purplemath.com/modules/quadprob2.htm
9. The product of two consecutive negative integers is 1122. What are the numbers?
a. Answer: -33 and -34
10. A garden measuring 12 meters by 16 meters is to have a pedestrian pathway installed all around
it, increasing the total area to 285 square meters. What will be the width of the pathway?
a. Answer: The pathway will be 1.5 meters wide.