Question

Bob's test increased from 75% to 90%. By what percent did his grade increase?

a. 15%
b. 12.5%
c. 20%
d. 18%

Answer 1

As Bob's test increased from 75% to 90%, his grade increase by c. 20%.

Step-by-step explanation:

To answer this question, we need to calculate the percentage increase in Bob's test grade from 75% to 90%. To do this, we will follow these steps:

1. Determine the absolute increase of Bob's test grade by subtracting the initial grade from the final grade:
Absolute increase = Final grade - Initial grade

2. Calculate the percentage increase by dividing the absolute increase by the initial grade and then multiplying by 100 to convert it to a percentage:
Percentage increase = (Absolute increase / Initial grade) * 100

Now, let's calculate the absolute increase and percentage increase:

1. Absolute increase:
Absolute increase = 90 - 75 = 15

2. Percentage increase:
Percentage increase = (15 / 75) * 100
= (1 / 5) * 100
= 20%

Therefore, the percentage increase of Bob's test grade is 20%, which corresponds to option c. 20%.