Question

A student missed

15 problems on a Chemistry test and received a grade of
52 %. If all the problems were of equal value, how many problems were on the test? Round off your answer to the nearest integer.

Answer 1

x = 31

Explanation:

Let x: total amount of questions in the Chemistry test.

Then 52% represents the ratio of questions properly answered vs total questions:

`(Correct)/(Total) = 52%`

The number of correct questions is the number of total questions take the number of missed questions.

`Correct questions = Total questions - missed questions`

Since, missed questions = 15

`(x-15)/(x) = 52%`

Also, 52% can be expressed as 0.52. Then, the expression can be rewritten as:

`(x-15)/(x) = 0.52`

Then, rearranging:

`x - 15 = 0.52x`

`x - 0.52x = 15`

`0.48x = 15`

`x = 15/0.48`

`x = 31.25`

Rounding to the nearest unit: x = 31