The area of the 48 contiguous states is 3.02 x 106 miles2. Assume that these states are completely flat, no mountains and no valleys. What mass of water would cover these states with a rainfall of two inches?

1 mile = 1,609 meters

3.02E6 mi^2 x (1609^2m^2/mi^2) = 7.818E12 m^2

1 in= 2.54 cm => 2 in = 5.08cm = .0508m

7.818E12 m^2 x .0508m = 3.97E11 m^3

1 cubic meter = 1,000,000 cubic centimeters

3.97E11 m^3 x (1,000,000 cm^3 / m^3) = 3.97E17 cm^3

1000 cm^3 = 1L

3.97E17 cm^3 x (1L / 1000cm^3) = 3.97E14 L  

or 3.97 x 10^14 L

convert to grams since 1L is 1000g

(3.97x10^14) x1000g which is 3.974x10^ 17g which is the final ans

Explanation:

the answer is option a.