I have the same difficulty. Once I get to the 700+ questions, I either spend too much time solving them or get the wrong answer.

Kaplan is right on this one. Here is the solution: [spoiler]The sum of all five numbers is 5*24=120 The sum of the numbers who have the average 18 is 18*2=36 Hence, the sum of other three numbers is 120-36=84. Now, since we want the largest possible value, then the rest of the numbers should have th...