Problem Solving

How to solve it in short time.

Mr. Kramer, the losing candidate in a two-candidate election, received 942,568 votes, which was exactly 40 percent of all the votes cast. Approximately what percent of the remaining votes would he need to have received in order to have won at least 50 percent of all the votes cast?
(A) 10%
(B) 12%
(C) 15%
(D) 17%
(E) 20%

Ans=D

In this question the number of votes is irrelevant, let me show you why

lets say x = total votes

Now we know Kramer has = 0.4x votes
To get to 0.5 (50%) votes he needs 0.1x

so the % of votes he needs out of remaining votes (60%) is

(0.1x/0.6x) * 100 = 100/6 ~ 17

That is a very good way to solve the problem!