How many pounds of pear does carrie buy?

Question

Carrie is buying fruit for a party. She buys a total of 18 pounds of pears and bananas. She spends $32.50 at the market. Pears cost $2.50 a pound and bananas cost $1.25 a pound. How many pounds of pears does carrie buy?

Answer 1

Here's what we know:

p + b = 18 (pear and banana weight totals 18 pounds)

2.5p + 1.25b = 32.50 (total cost for everything is $32.50)

 

Let's isolate b so that we can use the substitution method:

b = 18 - p

2.5p + 1.25(18 - p) = 32.5

Distribute:

2.5p + 22.5 - 1.25p = 32.5

Simplify:

1.25p + 22.5 = 32.5

 

All you need to do is isolate p from here.