Question

Miguel asked Sandra to make 90 cookies for his party. Sandra needs ¼ cup of sugar to make 15 cookies. She incorrectly calculated the amount of sugar she will need.

Answer 1

See below.

Explanation:

She needs to find the amount of sugar needed to make 1 cookie , then multiply the result by 90.

This amount is found by dividing 1/4 by 15. Instead of dividing she multiplies these numbers.

Correct is:

Amount of sugar for 1 Cookie = 1/4 / 15 = 1/60 cups.

Amount of sugar for 90 cookies = 90 * 1/60

= 3/2 = 1 1/2 cups.