Answer:
0.0975 or 9.75%
Step-by-step explanation:
Assuming that no engines fail simultaneously, the probability that exactly one engine fails is the probability that the first engine fails (15%) multiplied by the probability that the second engine does not fail (100% - 35%):

The probability of exactly one engine failure is 0.0975 or 9.75%
There are 72 different ways the director can fill the positions.
(1+2+3+4+5+6+7+8) x 2
You multiply it by 2 because there are going to be 4 other people who will not have a position, and 8/4 is 2.
Well Those are variables and it is using the Distributive property to solve. For example P(a+b) simplify P*a + P*b.
All the choices are correct.
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In our base-10 number system, moving a digit one place to the left multiplies its value by 10. Moving it one place to the right multiplies its value by 1/10.
You know already that 1,000 has 10 times the value of 100, and 1/10 the value of 10,000.