Question

Four pounds of apples cost $5. Eight pounds of apples cost $10. If the total cost of apples, y, varies directly with the number of pounds of apples purchased, x, what is the cost of 6 pounds of apples? Round your answer to the nearest hundredth.

Answer 1

5/4 = 1.25 per lb

1.25 * 6 = $ 7.50 <==

Answer 2

The cost of the 6 pounds of apples is $7.5 .

Explanation:

As y = Total cost of the apple.

x = The number of pounds of apples purchased .

As given

If the total cost of apples, y, varies directly with the number of pounds of apples purchased, x.

i.e

`y \propto x`

y = kx

Where k is the constant of proportionality .

As given

Four pounds of apples cost $5.

x = 4 , y = 5

Put in y = kx

5 = 4k

`k = (5)/(4)`

k = 1.25

Eight pounds of apples cost $10.

x = 8 , y = 10

Put in y = kx

10 = 8k

`k = (10)/(8)`

k = 1.25

Now find out the cost of 6 pounds of apples.

x = 6 and k = 1.25

Put in the y = kx

y = 6 × 1.25

y = $7.5

Therefore the cost of the 6 pounds of apples is $7.5 .