Question

Today, Reza ate 20 grapes, which was 400% as many grapes as he ate yesterday. Explain how to use equivalent ratios to find the number of grapes Reza ate yesterday.

Answer 1

Answer: 5 grapes.

Step-by-step explanation: Reza ate 20 grapes, which is 400% her amount yesterday. Turning the percent into a fraction/ratio would make 400/100. 4/1 is the equivalent fraction I’ll use. The equation would be 400/100 ÷ 4/1, or 400 ÷ 4 and 100 ÷ 1. The result is 100/100. Now, divide 100 (numerator of the answer to the first equation) to 20 (number of grapes Reza are today) to get an answer of 5. Reza ate 5 grapes yesterday.

Answer 2

What you must do for this case is to extract the relationship of the grapes that were eaten yesterday among the grapes that were eaten today.
To do it, let:
x: number of grapes that Reza ate yesterday
(x / 20) = (100/400).
Clearing x we have:
x = (100/400) * (20) = 5
answer
the number of grapes Reza ate yesterday was 5