Question

Test score raised from an 80 to a
90.
What was the percent increase?

Answer 1

12.5 % increase.

Explanation:

First, we calculate the amount of increase from 80 to 90 by subtracting the initial value from the final value, like this:

90 - 80= 10

To calculate the percent of any number, you multiply the value (n) by the percent (p) and then divide the product by 100 to get the answer, like this:

(n × p) / 100 = Answer

In our case, we know that the initial value (n) is 80 and that the answer (amount of increase) is 10 to get the final value of 90. Therefore, we fill in what we know in the equation above to get the following equation:

(80 × p) / 100 = 10

Next, we solve the equation above for percent (p) by first multiplying each side by 100 and then dividing both sides by 80 to get percent (p):

(80 × p) / 100 = 10

((80 × p) / 100) × 100 = 10 × 100

80p = 1000

80p / 80 = 1000 / 80

p = 12.5

Hence, when the test score raises from 80 to 90, it was a 12.5 % increase.

Answer 2

80/90= 0.8888 and 0.8888x100=88.88 (so either 88.88% or 89%)