Question

Test worth 75 points ; test score of 96%

Answer 1

According to given information, your marks would be:
75 * 96 / 100 = 75 * 0.96 = 72

So, you obtained 72 marks out of 75.

Hope this helps!

Answer 2

Presuming the question is "How many points did he miss", you would find the solution by multiplying the amount of possible points by the test score as a fraction. 96% is the fraction $\frac{96}{100}$. Therefore, you get the equation $75*\frac{96}{100}$. This is equal to 72, so he missed 3 points, or 75-72 points. 

He missed 3 points.