Variables in answers

Official Guide practice (find these in your Official Guide or at www.gmatclub.com). Even if you think you can solve these problems with algebra, try out the strategy of variables in the answers: smart numbers

PS03972 If 1 < x < y < z, which of the following has the greatest value?

PS16823 David has d books, which is 3 times as many as Jeff

PS07357 If Q is an odd number and the median of Q consecutive integers is 120,

PS08385 A total of s oranges are to be packaged in boxes

PS00526 When n liters of fuel were added to a tank

PS12577 Alex deposited x dollars into a new account that earned 8 percent annual interest,

PS16214 For the positive numbers, n, n + 1, n + 2, n + 4, and n + 8, the

PS01315 The harvest yield from a certain apple orchard

PS07465 In Western Europe, x bicycles were sold

PS16830 To mail a package, the rate is x cents for the first pound and y cents

PS08399 The number line shown contains three points R, S, and T,

PS04089 A certain high school has 5,000 students.

Go back and solve these problems with algebra. Which strategy is easier for each problem? Why?

Challenge problems

Do these problems only if you’re scoring 80+ in the quant section of your practice tests. Time yourself 2.5 minutes per problem and do the best that you can, even if that means guessing. Then take time to review the problems in depth, solving both with algebra and with variables in the answers: smart numbers.         

PS00428 Working simultaneously at their respective constant rates, Machines A and B produce 800

nails in x hours.        

PS08570 During a trip, Francine traveled x percent of the total distance

PS07459 Four extra-large sandwiches of exactly the same size were ordered for m students

PS08732 A sequence of numbers a1, a2, a3, . . . is defined as follows: a1 = 3, a2 = 5,

PS08552 Last year the price per share of Stock X increased by k percent

PS03144 Last Sunday a certain store sold copies of Newspaper A for $1.00 each

PS16896 In an electric circuit, two resistors with resistances x and y are connected in parallel. In this

case, if r is the combined resistance of these two resistors,