Bunuel
Which of the following cannot be the range of a set consisting of 5 odd multiples of 9?
(A) 72
(B) 144
(C) 288
(D) 324
(E) 436
Kudos for a correct solution. VERITAS PREP OFFICIAL SOLUTION:There are infinite possibilities regarding the multiples of 9 that can be included in the set. The set could be any one of the following (or any one of the other infinite possibilities):
S = {9, 27, 45, 63, 81} or
S = {9, 63, 81, 99, 153} or
S = {99, 135, 153, 243, 1071}
The range in each case will be different. The question asks us for the option that ‘cannot’ be the range. Let’s figure out the constraints on the range.
A set consisting of only odd multiples of 9 will have a range that is an even number (Odd Number – Odd Number = Even number)
Also, the range will be a multiple of 9 since both, the smallest and the greatest numbers, will be multiples of 9. So their difference will also be a multiple of 9.
Only one option will not satisfy these constraints. Do you remember the divisibility rule of 9? The sum of the digits of the number should be divisible by 9 for the number to be divisible by 9. The sum of the digits of 436 is 4 + 3 + 6 = 13 which is not divisible by 9. Hence 436 cannot be divisible by 9 and therefore, cannot be the range of the set.
Answer (E).