GRE Math Problem 72

Compare two values:

Column A	Column B
The average (arithmetic mean) of all the positive multiples of 5 less than 26	The average (arithmetic mea: of all the positive multiples of 7 less than 26

GRE Math Problem 56

Camille's average on her 6 math tests this marking period is 75. Fortunately for Camille, her teacher drops each student's lowest grade, and this raises her average to 85. What was her lowest grade?
(A) 20
(B) 25
(C) 30
(D) 40
(E) 50


Solution for GRE Math Problem 55:
The average of a, b, c, d, e,f, and g equals to their sum, divided by their quantity. So,

Answer: A

GRE Math Problem 30

Compare two values:

Column A	Column B
The number of positive three-digit numbers for which the average (arithmetic mean) of the three digits is equal to 2	20

Solution for GRE Math Problem 29:

Answer:(E)

GRE Math Problem 29

What is the average (arithmetic mean) of 3³⁰, 3⁶⁰, and 3⁹⁰?
(A) 3⁶⁰
(B)3¹⁷⁷
(C)3¹⁰ + 3²⁰ + 3³⁰
(D) 3²⁷ + 3⁵⁷ + 3⁸⁷
(E)3²⁹+3⁵⁹+3⁸⁹

Solution for GRE Math Problem 28:

Is the class average before the adjustment was A, then the average of missed points was 100-A. After the adjustment, the average of missed points became . So, the average of points gained became
Answer:(A)

GRE Math Problem 28

Because her test turned out to be more difficult than she intended it to be, a teacher decided to adjust the grades by deducting only half the number of points a student missed. For example, if a student missed 10 points, she received a 95 instead of a 90. Before the grades were adjusted the class average was A. What was the average after the adjustment?
(A)
(B)
(C)
(D)
(E)A+25

Solution for GRE Math Problem 27:
The sum of all vertical segments in the path P-R-T equals to the vertical distance between P and T. The sum of all horizontal segments in the path P-R-T equals to the horizontal distance between P and T. The same for the path P-Q-T. So, these paths are equal.
Answer:C

GRE Math Problem 20

If x + y = a, y + z = b, and x + z = c. what is the average (arithmetic mean) of x, y, and z?
(A)
(B)
(C)
(D)
(E) a+b+c

Solution for GRE Math Problem 19:

Let X be Jordan's average of test scores after 5 tests. Then, he got total 5X points after 5 tests. If he gets 70 points after the next test, he'll have 5X+70 points. His average will be points. But it is given, that his average will be lower by 4 points. We have an equation:

5X+70=6X-24
X=94

Answer:(E) 94

GRE Math Problem 19

Jordan has taken 5 math tests so far this semester. If he gets a 70 on his next test, it will lower the average (arithmetic mean) of his test scores by 4 points. What is his average now?
(A) 74 (B) 85 (C) 86 (D) 90 (E) 94

Solution for GRE Math Problem 18:

According to the trianglae unequation, if a triangle has sides of a and (a > =b), it is true for the third side, c, that a-b < c < a+b. Then, among the possible values for c, only (II) 11 fits the tringle unequality: 10-9 < 11 < 10+11.

Answer:(C) II only

GRE Math Problem 12

Given: The average (arithmetic mean) of the measures of two angles of a quadrilateral is 60°.

Compare two values:

Column A	Column B
The average of the measures of the other two angles	120°

Solution for GRE Math Problem 11:

Average of x and y lies exactly in the middle between x and y. Average of x, y and y lies between x and y, but closer to y. As y is bigger than x, columb B is greater.
Answer:B

GRE Math Problem 11

Given: x<y
Compare two values:

Column A	Column B
The average (arithmetic mean) of x and y	The average (arithmetic mean) of x, y, and y

Solution for GRE Math Problem 10:

In 1990 for twice less money we could buy twice more potatoes. So, the cost became 2x2=4 times less than in 1980. So, the price in 1990 was a quarter or 25% of the price in 1980. But the question is “By what percent did the price of potatoes decrease from 1980 to 1990?” Assuming price in 1980 as 100%, we get 100%–25%=75%
Answer:C