Last Updated on May 5, 2023
GMAT OFFICIAL GUIDE PS –
Solution:
When we divide decimals without a calculator, it is easier if we first convert all of the decimal numbers to whole numbers. If we move the decimal point of the decimal in the denominator to the right so that it becomes a whole number, we must also move the decimal point of the numerator to the right by the same number of places. Furthermore, if the denominator is a product of several decimals, such as the one in the problem, we can move the decimal point of each decimal until each becomes a whole number and count the total number of decimal places we have moved, and that will be the number of decimal places we move the numerator. Looking at the denominator of our problem:
If we move the decimal point of 0.04 two (2) places to the right, it will become 4.
If we move the decimal point of 0.1 one (1) place to the right, it will become 1.
If we move the decimal point of 0.003 three (3) places to the right, it will become 3.
Therefore, in the denominator, we have moved a total of 2 + 1 + 3 = 6 decimal places to the right. We must do the same for the numerator.
If we move the decimal point of 0.0036 four (4) places to the right, it will become 36. Since we have to move a total of 6 decimal places to the right, and we have already moved 4 decimal places to the right, we have to move the decimal point of 2.8 two (2) places to the right. So 2.8 will become 280.
Answer: A
