Hello there! To solve this question, we don't have to put those long numbers in the calculator, because that's just too complicating. Instead, we can convert each number into scientific notation and solve from there. Scientific notation is when you multiply a number greater than or equal to 1 but less than 10 by a power of 10. 330 million in scientific notation is 3.3 * 10^8, because 10^8 is 100 million. 147.2 billion is 1.472 * 10^11 power, because 10^11 is 100 billion. Now, what we do is multiply 3.3 and 1.472 together. 3.3 * 1.472 is 4.8576. Now, we add the exponents together. 8 + 11 is 19. There. There are about 4.8576 * 10^19 cubic miles of water on Earth.
Note: To break it down, you multiply the numbers being multiplied by the power of 10 together first, and then add the exponents to get to a product in scientific notation.
If we divide 800/1000, we get .8 This means The price of $800 is only 80% of $1000. Furthermore, this also means that there was a decrease in price of 20%. The answer is C.
