Question

A school club sold 220 T-shirts for a fundraiser. Adult-size shirts cost $20 each and child-size shirts cost $15 each. The total collected for all the T-shirts sold was $3,550.

How many adult-size T-shirts were sold?

Answer 1

{20a+15c=3550
{a+c=220

{20a+15c=3550
{15a+15c=3300
5a=250
a=50
There are 50 adult-size T-shirts were sold

Answer 2

Answer: There are 50 adult-size shirts that were sold .

Explanation:

Since we have given that

Cost of adult-size shirts = $20

cost of child-size shirts =$15

Let hte number of adult-size shirt be x

Let the number of child-size shirt be y

According to question,

`20x+15y=\$3550----------------------------(1)\\\\x+y=220---------------------------(2)\\\\`

So, we will use "Substitution method" :

`x+y=220\\x=220-y`

Put this value in equation (1):

`20x+15y=3550\\\\20(220-y)+15y=3550\\\\4400-20y+15y=3550\\\\4400-5y=3550\\\\4400-3550=5y\\\\850=5y\\\\(850)/(5)=y\\\\170=y`

So, put the value of y in x :

`x=220-y\\\\x=220-170\\\\x=50`

Hence, there are 50 adult-size shirts that were sold .