Answer:
7/225
Step-by-step explanation:
There are 15 marbles in the bag. The probability of drawing a red marble is 3/15 = 1/5. If you replace that marble, then the probability of drawing a blue marble is 5/15 = 1/3 and if you replace that marble, then the probability of drawing a white marble is 7/15. Therefore, the probability of drawing a red, blue and white marble with replacement is (1/5)(1/3)(7/15) = 7/225