Step-by-step explanation:
37 x 10^2 = 3700
First of all, we need to deduce the price of a single camera:

Now, we know that he profits 36 dollars from each camera. So, we are asking: which percentage of 150 is 36? We have

This equation literally says: 36 is x-percent of 150. And we need to solve for x:

Okay well here is the easy way: STEP 1. convert your percentage to a decimal 40%=.4 STEP 2. multiply 30 by the decimal: 30*.4=12. ANSWER: 40% OF 30 IS 12