Question

It requires 15 gallons of fertilizer to fertilize 5 fields how many gallons are needed to fertilize 7 fields

Answer 1

21 gallons

Explanation:

15/5=3

3*7=21

Answer 2

21 gallons

Explanation:

We can write a ratio

15 gallons x gallons

----------------- = ------------

5 fields 7 fields

Using cross products

15*7 = 5x

Divide each side by 5

15/5 *7 = 5x/5

3*7 =x

21

He will need 21 gallons