When the bag is full (of 10 marbles), there are 3 pink marbles. Thus, the probability of drawing a pink marble is 3/10.
We don't replace that pink marble. So now we have 9 marbles instead of 10. We now have 2 pink marbles in the bag. The probability of drawing a pink one now is 2/9.
Thus, the probability of drawing 2 pink marbles in a row is (3/10)(2/9), or
