TO WHOEVER CAN GET IT RIGHT

B and E

I used a calculator, it’s correct

1.) P(z < 2.87) = 0.9979

2.) P(z <  (240 - 240)/100) = P(z < 0) = 0.5
Required percentage = 50%

3.) P(z < (150,000 - 120,000)/30,000) = P(z < 1) = 0.84134
Required number of cars = 0.84134 x 6,000 = 5,048

4.) Required z-score = 0.27

5.) Let the required number of home owners be x, then P(z > (x - 42)/3.2) = 0.75
1 - P(z < (x - 42)/3.2) = 0.75
P(z < (x - 42)/3.2) = 0.25
P(z < (x - 42)/3.2) = P(z < -0.6745)
(x - 42)/3.2 = -0.6745
x - 42 = -2.1584
x = -2.1584 + 42 = 39.84 ≈ 39.9