Given:
Original or base : 40
New amount : 72
We need to find the difference of the new amount and the original amount
72 - 40 = 32
We then divide the difference by the original amount
32/40 = 0.80
We multiply the quotient by 100%
0.80 x 100% = 80%
The percentage of change is 80%
Answer: C.-1.5
Step-by-step explanation:
Given: The burning time of a very large candle is normally distributed with mean
of 2500 hours and standard deviation
of 20 hours.
Let X be a random variable that represent the burning time of a very large candle.
Formula: 
For X = 2470

So, the z-score they corresponds to a lifespan of 2470 hours. =-1.5
Hence, the correct option is C.-1.5.
9.89%
You can get this number by multiplying the two together.
Answer:
Water needed for pool = 486 cubic feet
Plastic liner required for the pool = 298.3 feet
Step-by-step explanation:
Top view of the pool is a composite figure, having one rectangle and a trapezoid.
1). Water needed for the pool = volume of the pool
Volume of the pool = Area of the base × Depth
= (Area of the rectangle + Area of the trapezoid)× depth
Area of the trapezoid = 
= 
= 105 ft²
Area of the rectangle = Length × width
= 11 × 1.5
= 16.5 ft²
Now, volume of the pool = (105 + 16.5) × 4
= 121.5 × 4
= 486 cubic feet
b). Liner required = surface area of the pool excluding top
= Surface area of the walls + Area of the pool base
= (Perimeter of the pool) × depth + area of the base
= (12 + 11 + 1.5 + 10.7 + 9)×4 + 121.5
= 176.8 + 121.5
= 298.3 square feet
Therefore, amount of water required = 486 cubic feet
liner needed = 298.3 square feet