Question

How many problems must be answered correctly on a math test with 60 problems to get a score of 85%

Answer 1

`\begin{array}{ccc}60&-&100\%\\x&-&85\%\end{array}\\\\\text{cross multiply}\\\\100\cdot x=60\cdot85\\\\100x=5100\ \ \ |:100\\\\\boxed{x=51}`

Answer: 51 problems.

Answer 2

You would have to answer 51 questions correctly. To get this, multiply .85 (85% as a decimal) by 60. So 51 is 85% of 60.