MentorTutoring wrote:
Farina wrote:
An investment is made at 12.5% annual simple interest. The number of years it will take for the cumulative value
of the interest to equal the original investment is
(A) 4
(B) 5
(C) 6
(D) 7
(E) 8
Farina, I did not know you were posting your own questions now. Thank you for sharing. As for this one, since the problem mentions
simple annual interest, we are really just looking for how many times 12.5 fits into 100:
per cent means
for each hundred, and we know that the investment will keep earning 12.5 percent of the principal per year. I would not--I did not--even bother with an algebraic framework. Rather, I looked at the question as a multiplication problem and reinterpreted it:
Which of the following, when multiplied by 12.5, yields a product of 100?\((12*8)+(0.5*8)\)
\((96)+(4)\)
\(100\)
The answer is (E). I prefer to split my multiplication of decimals and other types of numbers just to keep from having to write anything down sometimes. It often proves to be a timesaver, and this one was no exception.
Thank you again for sharing.
- Andrew
Hey Andrew, it is not my own question, it is from Manhattan 5 LB Book of GRE. Since this name was not mentioned in the tags (only
Manhattan GMAT is there) so I selected "other source".
Thank you for explanation, I calculated like this too, I just didn't split the numbers though, that's a good trick, thanks a lot