If I have 3 apples and 2 pears and I spent a total of 3 dollars and I know apples cost half as much as pears. What did I spend on apples and pears?

Question

If I have 3 apples and 2 pears and I spent a total of 3 dollars and I know apples cost half as much as pears. What did I spend on apples and pears?

Answer 1

Let a be the cost of an apple 

let p be the cost of a pear 

 

what are the equations that relate these numbers?

 

total cost of fruit

3 = 3a + 2p

 

cost relationship

2a=p

 

to solve, substitute p =2a into other equation

3 = 3a + 2(2a)

combine terms

3 = 3a + 4a

3 = 7a

a = $3/7 = $0.429

 

substitute into either formula

p = 2*(3/7) = $6/7 = $0.858