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Word Problems Create and solve a system of equations to answer each word problem Kristen spent $131 on shirts. Fancy shirts cost $28 and plain shirts cost $15. If Kristin bought a total of 7 shirts, how many of each kind did she buy? #1 Let x = # of plain shirts (-15) x + y = 7 15x +28y = 131 - 15x - 15y = -105 Let y = # of "fancy" shirts x +2 = 7 -2 -2 x =5 15x +28y = 131 13y 26 = 13 13 y =2 Final Answer : 5 plain shirts and 2 fancy shirts A piggy bank holds $3.35 worth of nickels and quarters. If there is a total of 19 coins in the piggy bank, find the number of nickels and the number of quarters in the piggy bank. #2 Let x = # of nickels (-5) x + y = 19 5x +25y = 335 - 5x - 5y = -95 Let y = # of quarters x + 12 = 19 - 12 - 12 x=7 5x +25y = 335 20y 240 = 20 20 y = 12 Final Answer : 7 nickels and 12 quarters The debate club sells pizza after school as a fundraiser. Plain slices cost $1.50 while Meatball slices cost $2.50. The club sold a total of 82 slices of pizza and made a total of $173. How many plain slices and how many meatball slices did they sell? #3 Let x = # of plain slices Let y = # of meatball slices (-1.5) x + y = 82 x + 50 = 82 1.5x +2.5y = 173 - 50 - 1.5x - 1.5y = -123 x = 32 - 50 1.5x +2.5y = 173 y = 50 Final Answer : 32 plain slices and 50 meatball slices There are 13 animals in a barn. Some are chickens and some are pigs. The animals have a combined total of 40 legs. How many of each animal is there? #4 Let x = # of chickens (-2) x + y = 13 2x + 4y = 40 -2x -2y = -26 Let y = # of pigs x + 7 = 13 -7 x =6 2x + 4y = 40 2y 14 = 2 2 y =7 Final Answer : 6 chickens and 7 pigs -7 I am thinking of two numbers: The first number plus three times the second number equals 36. The second number is five more than two times the first number. Find both numbers. #5 Let x = the first number Let y = the second number x + 3y = 36 y = 2 (3) + 5 y = 2x + 5 y =6+5 x + 3(2x + 5 ) = 36 y = 11 x + 6x + 15 = 36 7x + 15 = 36 - 15 -15 7x 21 = 7 7 x =3 Final Answer : The first number is 3 and the second number is 11