Manuel's grade on a science quiz was 80%. He got 20 problems correct on the quiz. How many problems were on the science quiz?

There were 25 problems on the science quiz

Step-by-step explanation:

1. Let's review the information provided to us to answer the question correctly:

Grade Manuel got on the science quiz = 80% or 80/100

Number of correct answers = 20

2. How many problems were on the science quiz?

Let's use the Rule of Three Simple, this way:

Problems on the science quiz Percentage

20 80

x 100

x * 80 = 20 * 100

80x = 2,000

x = 2,000/80

x = 25

There were 25 problems on the science quiz

25

Step-by-step explanation:

20 x 100/80 = 25

or 20/80 = x/100