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.
To use equivalent ratios to find the number of grapes Reza ate yesterday, we need to set up a ratio comparing the number of grapes he ate today to the number of grapes he ate yesterday.
Let's start by assigning a variable to represent the number of grapes Reza ate yesterday. Let's call it "x".
According to the problem, Reza ate 20 grapes today, which is 400% as many grapes as he ate yesterday.
To find the number of grapes Reza ate yesterday, we can set up the following ratio:
20 grapes today / x grapes yesterday = 400% / 100%
Since 400% is equal to 4, 400% / 100% simplifies to 4/1.
So, the equivalent ratio is:
20 / x = 4 / 1
Now we can cross-multiply and solve for x:
20 * 1 = x * 4
20 = 4x
Dividing both sides of the equation by 4:
20 / 4 = 4x / 4
5 = x
Therefore, Reza ate 5 grapes yesterday.