The initial y value can be found by setting x to 0. Anything to the power of 0 is 1, so 1.71^x when x is 0 is just 1. 60*1=60, which is the initial y value. Hope this helps!
For starters, the probability of finding any of these colors is a 50/50 type of thing, or in this case, an equal quarter. So each would be 1/4, or 25%. Unless, of course, they're lying about having one or more colors of marbles in their possession. But I'm answering under the assumption that they're not.
