Wednesday, June 17, 2009

Problem 51 - GMAT Number Properties

How many multiples of 2 or 5 are there between 20 and 80, inclusive?

(A) 37
(B) 39
(C) 41
(D) 42
(E) 44

3 comments:

  1. Answer iS A there are 37 multiples of 2 and 5

    ReplyDelete
  2. 20,22,24...80
    Tn= a+(n-1)2
    n=31

    Multiples of 5 not listed above are:
    25,35,45,55,65,75

    Total: 31+6=37

    ReplyDelete
  3. its a typical set problem

    A) multiples of 2 = (80-20/2) +1 = 31
    B) multiples of 5 = (80-20/5) +1 = 13
    C) multiples of 2 & 5(ie 10) = (80-20/10) + 1 = 7

    total no of multiples = A+B-C = 31+13-7 = 37 OA A

    ReplyDelete