SOLUTION: The part is 350 and the whole is 200 (note that the part can be
greater than the whole). The solution is thus:
350200 = 100 p
200350 × 100 = p
3502 = p
175 = p60% of what number is 540?SOLUTION: The part is 540, and the whole is unknown. Thus:(^540) p = 10060
(^540) p =^35
540(5) = 3p
p = 900
Percent Change
Some GRE questions will ask you to calculate the percent by which a certain value
increases or decreases. For example:
If the price of a shirt increased from $80 to $100, then by what percent did
the price of the shirt increase?
Any time you are asked to solve for percent change, use the following formula:
percent change = originalchange × 100
When using this formula, make sure that the denominator is the original value
and that the value in the numerator is positive. In the given example, the change is
100 – 80 = 20. The original value is the price of the shirt before the increase, in this
case, $80. Thus the percent change =^2080 × 100 = 25%.
In the preceding example, you knew the original value and the new value, and
you were asked to solve for the percent change. What if you are told the percent
change and are asked to solve for the original or new value? Use the following
formulas:
If a quantity increases by p percent, the new quantity will equal (100 + p)% × the
original quantity.
If the price of a $3,000 computer increased by 20%, what is the new price?
SOLUTION: Since the price increases by 20%, the new price will be (100% +
20%) × $3,000 = 120% × 3,000 = 1.2 × $3,000 = $3,600.
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