I need to understand how to do the problem and not the answer.

P.S. bobpursley, no offense but I didn't understand what your response meant. That information I already know but I need to know how to do the problem to get 213 as the answer.

Anida won the class election by margin of 5-3. She received 355 votes. How many votes did the other candidates get? Answer:213

Another way to solve this problem is to set up a proportion.

5 / 3 = 355 / x

Cross multiply:

5x = 1065
x = 213