Question 465745: Hello,
I am not sure how to go about answering the following questions to come up with the correct answers. Could you show me step by step how to solve this and that way I can elarn how to solve the other problems like this.
Water in Lake:
East Battle Lake in Minnesota covers an area of about 1950 acres or 8.5 x 10^7 square feet and its average depth is about 3.2 x 10^1 feet.
A. Estimate the cubic feet of water in the lake.
Volume = area x average depth.
B. One cubic foot of water equals about 7.5 gallons.
How many gallons of water are in this lake?
C. The population of the United States is about 3.02 x 10^8, and the average America uses about 1.5 x 10^2 gallons of water per day. Could this lake supply the American population with water for 2 day?
Answer by kingme18(98)   (Show Source):
You can put this solution on YOUR website! A. Even though you were given the number of acres, you're not using it at all in this problem, so ignore the 1950. Since Volume = area * average depth, we're going to multiply  . When multiplying things that are in scientific notation, multiply the numbers out front, and multiply the 10's (since they're like bases, you'll use your rules of exponents):  . To truly be in scientific notation, the first number should be between 1 and 10, so instead of  , we'll rewrite it as  cubic feet.
B. Since each cubic foot is 7.5 gallons, and we have cubic feet, we'll just multiply:  . Again, we want the first number to be between 1 and 10, so this will turn into  gallons.
C. We're going to multiply everything, so that it's population * each person's use each day * 2 days:  Again, multiply the regular numbers, then deal with the 10's with their exponents:  . That is more than the from part B, so no, there would not be enough water in the lake.
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