You are the captain of the volleyball team and are in charge of ordering t shirts and sweatshirts. T shirts cost $8 and sweatshirts cost $22. If the total cost of the 60 shirts is $872, how many of each did you purchase?

1 Answer
Oct 29, 2016

Good communication (explaining what you are doing) is quite important. It could get you extra marks

There are 28 sweatshirts and 32 T-shirts

Explanation:

2 unknowns means you need 2 equations.

Let the count of sweatshirts be s
Let the count of T Shirts be t

Then we have

t+s=60 count.............Equation(1)

8t+22s=872 cost.......Equation(2)
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The trick is use these so that you only have 1 unknown in 1 equation.

Using Equation(1) t=60s

Substitute for t in Equation(2) giving:

8(60s)+22s=872 Only 1 unknown value, which is s

Multiply out the brackets

4808s+22s=872

480+14s=872

Subtract 480 from both sides

14s=392

Divide both sides by 14

s=28

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Substitute for s in Equation(1) giving

t+s=60 t+28=60

Subtract 28 from both sides

t=32

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