A large construction company has enough construction materials on hand to build 50 medium-sized homes. Each medium-sized home requires 200 cubic yards of concrete. Let X = the number of cubic yards of concrete required for a randomly chosen new home design. The probability mass function of X is:
X
200
400
600
800
1000
p(X)
0.4
0.25
0.2
0.1
0.05
Compute the expected value, E(X), and variance, V(X), of the number of cubic yards of concrete required for a randomly chosen new home design.
E(X) = 430
V(X) = 57100
The construction company is just finishing the 28th house in a new subdivision project that will require a total of 75 homes. On a trip to the warehouse, the project manager determines that the company has 700 cubic yards of concrete left, but has left the project plan at the office and doesn't recall which house they are scheduled to build next. What is the probability that they will be able to finish at least one more home without having to order more concrete?
P = 1.5
Answer 1:
430
Answer 2:
57100
Answer 3:
1.5