a = 42 cups
b = 11 cups
Explanation:
A) V = pi x r^2 x h
V = pi x (4/2)^2 x 8
V = pi x 2^2 x 8
V = pi x 4 x 8
V = 32pi (this is the volume of the cup)
To find the number of cups needed to scoop out all of the water in the sink, you have to use this equation: (sink volume)/(cup volume)
(4000/3 x pi)/(32pi)
the pi's cancel out
(4000/3)/32
41.6667 cups
But the problem said to round up, so it's 42 cups.
B) V = pi x r^2 x h
V = pi x (8/2)^2 x 8
V = pi x 4^2 x 8
V = pi x 16 x 8
V = 128pi (this is the volume of the cup)
To find the number of cups needed to scoop out all of the water in the sink, you have to use this equation: (sink volume)/(cup volume)
(4000/3 x pi)/(128pi)
the pi's cancel out
(4000/3)/128
10.41667 cups
But the problem said to round up, so it's 11 cups.