If x is the number of calls he makes and y is the number of hours he works; the total amount he charges is termed as C C = (50 * x) + (25 * y ) C = 50x + 25y 25y = C - 50x the 2 variables are not proportional. For 2 variables to be proportional, they need to be in the form y = mx Where m is a constant. When x increases, y too should increase by the same amount. The question given x and y are not proportional. As the number of hours he works and number of calls he charges are not dependent on each other. Therefore the 2 variables are not proportional.
If each shelf is to contain exactly 3 new CDs and there are only 5 shelves, only 15 can be placed in the rack. So, the answer to the second question is no. The same goes for the first question as placing 3 or fewer CDs to the shelves will make the rack insufficient for the CDs.
