Andrew Geller

Andrew Geller is a top GMAT tutor based out of New York City. Throughout his career he has successfully taught people from many different backgrounds, countries, and starting scores.

According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make an orange juice. How many 12 ounce cans of concentrate are required to prepare 200 6-ounce servings of orange juice?

According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make an orange juice. How many 12 ounce cans of concentrate are required to prepare 200 6-ounce servings of orange juice? (A) 25 (B) 34 (C) 50 (D) 67 […]

According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make an orange juice. How many 12 ounce cans of concentrate are required to prepare 200 6-ounce servings of orange juice? Read the Full Article »

If two of the four expressions x+y, x+5y, x-y, and 5x-y are chosen at random, what is the probability that their product will be of the form of x² – by², where b is an integer?

If two of the four expressions x+y, x+5y, x-y, and 5x-y are chosen at random, what is the probability that their product will be of the form of x² – by², where b is an integer? (A) 1/2 (B) 1/3 (C) 1/4 (D) 1/5 (E) 1/6 Be super comfortable with difference of squares. You’re almost

If two of the four expressions x+y, x+5y, x-y, and 5x-y are chosen at random, what is the probability that their product will be of the form of x² – by², where b is an integer? Read the Full Article »

A committee of 3 people is to be chosen from four married couples. What is the number of different committees that can be chosen if two people who are married to each other cannot both serve on the committee?

A committee of 3 people is to be chosen from four married couples. What is the number of different committees that can be chosen if two people who are married to each other cannot both serve on the committee? A. 16 B. 24 C. 26 D. 30 E. 32 GMAT combinatorics questions get demonized but

A committee of 3 people is to be chosen from four married couples. What is the number of different committees that can be chosen if two people who are married to each other cannot both serve on the committee? Read the Full Article »

The perimeter of a certain isosceles right triangle is 16 + 16√2. What is the length of the hypotenuse of the triangle? Three ways to solve this beast and a video solution!

(A) 8 (B) 16 (C) 4√2 (D) 8√2 (E) 16√2 A lot of people get this GMAT geometry question from the GMAT prep software wrong. It’s true that the algebra gets a little tricky but conceptually there’s not much going on. We just need some basic triangle rules and vocabulary (perimeter, isosceles, right triangle…) And,

The perimeter of a certain isosceles right triangle is 16 + 16√2. What is the length of the hypotenuse of the triangle? Three ways to solve this beast and a video solution! Read the Full Article »