We divide 60 by 2 as many times as possible to get 60 = 15 x 2 x 2. 2 is a prime number so we don't need to break the 2's down any more. Instead we break 15 down. 15 doesn't divide by 2 so we try the next prime number: 3 Divide 15 by 3 to get 15 = 5 x 3, and so 60 = 5 x 3 x 2 x 2.
Convention in algebra is that we use letters such as a, b, c, etc., for parameters and letters such as x, y z, and so on, for variables.
Thus the parameters here are a, b and k. k is the constant of proportionality.
The answer is D, tony would always be behind Robert.
