There are four times as many girls in a chemistry class as there are boys. if there are 45 students in the class, how many boys are in the class? type your answer in the box below.

In order to determine the number of boys in the class, first, we set-up an algebraic equation. Let x = number of boys in the class. The equation is then: x + 4x = 45. This is because the number of girls is 4 times greater than the number of boys. After solving the algebraic equation, it is then determined that there are 9 boys in the Chemistry class.   

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.