Question

Tessa needs 313 scoops of mulch to cover 10 square yards in her garden. Ten scoops of mulch would cover x square yards of her garden. If the unit rate remains the same, which of the following explains the value of x?

Answer 1

In checking for proportion:
a/b = c/d
where: cross products are equal.
ad = bc

313/10 = 10/x

313x = 10 * 10
313x = 100
313x/313 = 100/313
x = 0.319 or 0.32

313/10 = 31.3
10/0.32 = 31.25 or 31.3