Give a quick stream of consciousness before answering the following question. When N is divided by 10 the remainder is 1 and when N is divided by 3 the remainder is 2. What is the remainder S when N is divided by 30?
Options:
(A) (a) 4
(B) (b) 7
(C) (c) 11
(D) (d) 13
(E) (e) 17
N ends in the digit 1 because when N is divided by 10, the remainder is 1. Since N ends in 1, the remainder S when N is divided by 30 also ends in a 1. 11 is the only choice which ends in a 1.
The answer: (C).