Brent@GMATPrepNow wrote:When positive integer x is divided by 44, the remainder is 28. When positive integer y is divided by 22, the remainder is 14. If N = x+y, what is the remainder when N is divided by 11?
A) 1
B) 3
C) 5
D) 7
E) 9
Regor60's algebraic solution (above) is perfect.
In case some viewers are unfamiliar with this technique, here's a longer version:
When it comes to remainder questions, there's a useful rule that say, "
If N divided by D equals Q with remainder R, then N = DQ + R"
For example, since 17 divided by 5 equals 3 with remainder 2, then we can write 17 = (5)(3) + 2
Likewise, since 53 divided by 10 equals 5 with remainder 3, then we can write 53 = (10)(5) + 3
When x is divided by 44, the remainder is 28
We can rewrite this as "x divided by 44 equals some integer k with remainder 28"
So, x = 44k + 28 for some integer k
When integer y is divided by 22, the remainder is 14.
So, y = 22j + 14 for some integer j
N = x + y = (44k + 28) + (22j + 14)
N = 44k + 22j + 42
N =
44k + 22j + 33 + 9
N =
11(4k + 2j + 3) + 9
As we can see N is
9 GREATER than
some multiple of 11
So, when we divide N by 11, the remainder will be
9
Answer:
E
Brent Hanneson - Creator of GMATPrepNow.com
