A helicopter and a plane can make a safe landing if at least half of its engines are working properly. Suppose that engine failures are independent events. Determine whether a two engine helicopter or a four engine plane is safer if the chance that an engine fails is 1 in 100?

I'm going to make an uneducated guess here.

I think the probability of two engines failing would be the same for either aircraft. In the instance that does happen, the helicopter doesn't fly at all and the airplane does.

I say the airplane is safer.

Step-by-step explanation:

3x^3-x^2+6x-9

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40