Answer:
0.1353 = 13.53% probability that the lifetime exceeds the mean time by more than 1 standard deviations
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:

In which
is the decay parameter.
The probability that x is lower or equal to a is given by:

Which has the following solution:

The probability of finding a value higher than x is:

The mean time for the component failure is 2500 hours.
This means that 
What is the probability that the lifetime exceeds the mean time by more than 1 standard deviations?
The standard deviation of the exponential distribution is the same as the mean, so this is P(X > 5000).

0.1353 = 13.53% probability that the lifetime exceeds the mean time by more than 1 standard deviations
The area of a triangle is a+b+c
6. the answer is 4. because u find the diameter by dividing by 2.
7. answer = 8 , the radius is 4 . so u need to multiply 2 times 4. 2 times 4 =8.
For this problem you have yo set up two equations.
White shirts = w Yellow shirts = y
1st: w + y = 21
2nd: 9.95w + 11.50y = 235.30
Now we're going to do system of equations using substitution.
If w + y = 21, then y = 21 - w
If y = 21 - w, then you can substitute this in the second equation for y.
9.95w + 11.50(21 - w) = 235.30
9.95w + 241.5 - 11.50w = 235.30
-1.55w + 241.5 = 235.30
-1.55w = -6.2
w = 4, so 4 whites shirt were sold.
Now I'm finding out how many yellow shirts were sold using one of the two equations at the top.
w + y = 21
4 + y = 21
y = 17
So 17 yellow shirts were sold and 4 white shirts were sold.