What's the answer to this math problem

Total number of marbles:
75 + 50 + 100 + 25 = 250

Probability of selecting a red marble:
25/250 (since 25 out of 250 marbles are red)
Since the top and bottom of this fraction are both divisible by 25, we can go ahead and divide them both by 25, simplifying to 1/10.

Probability of selecting a green marble:
50/250
Simplifies to 2/10
Simplifies to 1/5.

Probability of selecting a blue or orange marble
(75+100)/250
175/250
Simplifies to 7/10.

To find the probability that each event occurs in order, simply multiply them all together.

The answer of this question is 672 .