Respuesta :

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.
gmany
[tex]\begin{array}{ccc}60&-&100\%\\x&-&85\%\end{array}\\\\\text{cross multiply}\\\\100\cdot x=60\cdot85\\\\100x=5100\ \ \ |:100\\\\\boxed{x=51}[/tex]

Answer: 51 problems.