Answer:
Z value for the first pump = -0.68
Z value for the second pump = 0.45
Step-by-step explanation:
Data provided in the question:
Mean labor cost to repair a heat pump = $90
Standard deviation = $22
Labor cost for the first, X₁ = $75
Labor cost for the Second, X₂ = $100
Now,
Z value for the first pump = [X₁ - Mean] ÷ Standard deviation
thus,
Z value for the first pump = [ $75 - $90] ÷ $22
= - 0.68
Z value for the second pump = [X₁ - Mean] ÷ Standard deviation
thus,
Z value for the second pump = [ $100 - $90] ÷ $22
= 0.45
The .mp3 player finally sells for $99.00 .
Original price . . . $100 .
Increase the original price by 10% .
(multiply by (100% + 10%) = 110% = 1.10)
(1.10) x ($100) = $110 .
Now decrease the $110 by 10% .
(multiply by (100% - 10%) = 90% = 0.90)
(0.90) x ($110) = $99 .
The formula is 4/3 times pi times radius cubed. The radius is 9. 4/3 is 1.33. 3.14 times 9 cubed is 81 times 3.14. That is 254.34. 1.33 times 254.34 is 338.2722. That rounds to 338.
Multiply everything if not that than add