- C You are asked to find the price of the shirt after a 20% decrease. In other
words, you want to solve for 0.8 (original price). If a 30% increase represents
$60, then $60 is 30% of the original price. Algebraically, you can represent this
as 0.3x = 60, where x = the original price. Solve for x:
0.3x = 60
x = 60/0.3
x = 200
Now reduce 200 by 20%: 200(100% – 20%) = 200(80%) = 200(0.8) = 160. - D To solve for percent increase, use the formula originalchange × 100. In this case, the
new value is the number of women students at the college in 2010, and the old
value is the number of women students at the college in 1980. The number of
women students in 2010 is 60% of 12,000 = 0.6(12,000) = 7,200. The number of
women students in 1980 is 30% of 4,000 = 0.3(4,000) = 1,200. Plug these values
into the formula: 7,200 – 1,2001,200 × 100 = 500%. - D First, identify what you’re solving for. To fill three 200-ounce vats, you will
need 600 ounces of jelly. To determine how many jars of jelly you need, you
will need to determine how many ounces are in an individual jar of jelly. Use
j to represent this value. You are told that 40% of j will fill a 200-ounce vat
to 25% of its capacity. 25% of 200 is 50, so you know that 40% of j = 50. Now
solve for j: 0.4j = 50 → j = 125. The number of jars you need will be^600125 = 4.8.
However, since you cannot have a fraction of a jar, you will need 5 jars to yield
the necessary amount of jelly to fill the three vats. - A Since the question asks for a percent, use the formula wholepart = 100 p. You must
determine the part and the whole. This is a percent question with no actual
amounts given, so the best approach is to plug in values. Let the original price
of a T-shirt be $100 and the original price of a blouse be $200. After a 50%
discount, the blouse will cost $100. After a 25% discount, the T-shirt will cost
$75. In total, Beth pays $175. Before the discounts, Beth would have paid $300.
Now find $175 as a percentage of $300:
175300 = 100 p
175(100) = 300p
1753 = p
p ≈ 58% - C Since you are not told how many additional freshmen enroll in the school,
assign a variable: x. You know that after x freshmen enroll in the school,
the number of freshmen will be 20% of all students. Since you are given a
relationship using percentages, use the formula:
part
whole =
percent
100CHAPTER 10 ■ PART-TO-WHOLE RELATIONSHIPS 23903-GRE-Test-2018_173-312.indd 239 12/05/17 11:52 am