example 3 standardized test practice solution write verbal models for this situation
TRANSCRIPT
EXAMPLE 3 Standardized Test Practice
SOLUTION
Write verbal models for this situation.
Equation 1
EXAMPLE 3 Standardized Test Practice
Equation 2
EXAMPLE 3 Standardized Test Practice
STEP 2 Write a system of equations.
Equation 1
Equation 2
5x + 7y = 2500
8x + 12y = 4200
Total cost for all T-shirts
Total revenue from all T-shirts sold
STEP 3Solve the system using the elimination method.
Multiply Equation 1 by –8 and Equation 2 by 5 so that the coefficients of x differ only in sign.
5x + 7y = 2500
8x + 12y = 4200
– 40x – 56y = – 20,000
40x + 60y = 21,000
Add the revised equations and solve for y. 4y = 1000y = 250
EXAMPLE 3 Standardized Test Practice
Substitute the value of y into one of the original equations and solve for x.
5x + 7y = 2500
5x + 7(250) = 2500
5x + 1750 = 2500x = 150
Write Equation 1.
Substitute 250 for y.
Simplify.
Solve for x.
The school sold 150 short sleeve T-shirts and 250 long sleeve T-shirts.
ANSWERThe correct answer is C.
GUIDED PRACTICE for Example 3
4.WHAT IF? In Example 3, suppose the school spends a total of $3715 on T-shirts and sells all of them for $6160. How many of each type of T-shirt are sold?
The school sold 365 short sleeve T-shirts and 270 long sleeve T-shirts.
ANSWER