A. We know that 3,300,000 gallons enter the river in a second. So Shana says that 200,000,000 gallons enter in a minute. There's 60 seconds in a minute, so multiply 3,300,000 by 60. We get 198,000,000. If we were to round up, we would get 200,000,000, which is Shana's estimate. So her estimate is fairly correct.
B. Divide 200,000,000 by 4. We should get 50,000,000 quarts.
