If xy + z = x(y + z), which of the following must be true? (A) x = 0 and y = 0 (B) x = 1 and y = 1 (C) y = 1 and z = 0 (D) x = 1 or y = 0 (E) x = 1 or z = 0 […]
If xy + z = x(y + z), which of the following must be true? Read the Full Article »
In a village of 100 households, 75 have at least one DVD player, 80 have at least one cell phone, and 55 have at least one MP3 player. If x and y are respectively the greatest and lowest possible number of households that have all three of these devices, x – y is: (A) 65
Pumps A, B, and C operate at their respective constant rates. Pumps A and B, operating simultaneously, can fill a certain tank in 6/5 hours; pumps A and C, operating simultaneously, can fill the tank in 3/2 hours; and pumps B and C, operating simultaneously, can fill the tank in 2 hours. How many hours
GMAT Explanation: Pump Operation Read the Full Article »
Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machines Y. At these rates, if the two machines together produce 5w/4 widgets in 3 days, how many days would it take machine X alone to produce 2w widgets. (A) 4 (B) 6 (C) 8 (D) 10 (E)
When a certain tree was first planted, it was 4 feet tall and the height of the tree increased by a constant amount each year for the next 6 years. At the end of 6 year the tree was 1/5 taller than it was at the end of 4 year. By how many feet did
