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.

Three printing presses, R, S, and T, working together at their respective constant rates, can do a certain printing job in 4 hours. S and T, working together at their respective constant rates, can do the same job in 5 hours. How many hours would it take R, working alone at its constant rate, to do the same job?

Three printing presses, R, S, and T, working together at their respective constant rates, can do a certain printing job in 4 hours. S and T, working together at their respective constant rates, can do the same job in 5 hours. How many hours would it take R, working alone at its constant rate, to […]

Three printing presses, R, S, and T, working together at their respective constant rates, can do a certain printing job in 4 hours. S and T, working together at their respective constant rates, can do the same job in 5 hours. How many hours would it take R, working alone at its constant rate, to do the same job? Read the Full Article »

List M (not shown) consists of 8 different integers, each of which is in the list shown. What is the standard deviation of the numbers in list M?

4, 6, 8, 10, 12, 14, 16, 18, 20, 22 List M (not shown) consists of 8 different integers, each of which is in the list shown. What is the standard deviation of the numbers in list M? (1) The average (arithmetic mean) of the numbers in list M is equal to the average of

List M (not shown) consists of 8 different integers, each of which is in the list shown. What is the standard deviation of the numbers in list M? Read the Full Article »

A department manager distributed a number of pens, pencils, and pads among the staff in the department, with each staff member receiving x pens, y pencils, and z pads. How many staff members were in the department?

A department manager distributed a number of pens, pencils, and pads among the staff in the department, with each staff member receiving x pens, y pencils, and z pads. How many staff members were in the department? (1) The numbers of pens, pencils, and pads that each staff member received were in the ratio 2:3:4,

A department manager distributed a number of pens, pencils, and pads among the staff in the department, with each staff member receiving x pens, y pencils, and z pads. How many staff members were in the department? Read the Full Article »