The length of time y necessary to complete a key operation in the construction of houses has an exponential distribution with mean 13 hours. the formula c = 100 + 80y + 3y2 relates the cost c of completing this operation to the square of the time to completion. the mean of c was found to be found to be 2,154 hours and the variance of c was found to be 10,440,820. how many standard deviations above the mean is 3,000 hours?

3000 hours is 0.2618 standard deviations above the mean.

Step-by-step explanation:

In this problem, we have that:

The mean of C was found to be found to be 2,154 hours and the variance of C was found to be 10,440,820.

How many standard deviations above the mean is 3,000 hours?

The first step to solve this problem is finding the standard deviation of C.

This is the square root of the variance of C.

We have that the variance of C is 10,440,820. So

Now, the number of standard deviation abve the mean of 3000 ours is given by:

3000 hours is 0.2618 standard deviations above the mean.

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons

-2x + 7 = 7

subtract 7 from both sides.

-2x = 0

divide both sides by -2.

x = 0