probability marble question

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I am having trouble answering this question from my text

can anyone help me?

A bag contains 8 blue marbles, 7 red marbles, and 5 green marbles

a) If you randomly select 3 marbles with replacement, what is the probability of drawing a red, a green and a blue marble in that order.

b) If you randomly select 3 marbles without replacement, what is the probability of drawing a red, a green, and a blue marble in that order.

c) If you randomly select marbles without replacement, what is the probability that at least 2 of them will be red.

Answers

a)0.035

b)0.041

c)0.2702