A certain sum was invested in a high-interest bond for which

Question

A certain sum was invested in a high-interest bond for which the interest is compounded monthly. The bond was sold x number of months later, where x is an integer. If the value of the original investment doubled during this period, what was the approximate amount of the original investment in dollars?

1) The interest rate during the period of investment was greater than 39 percent but less than 45 percent.

2) If the period of investment had been one month longer, the final sale value of the bond would have been approximately $2,744.

BG · Answer

On a first look think that it is B)

ywilfred · Answer

no other takers ? :-D

kapslock · Answer

I'd go with C (both combined suffice).

1) Gives us the rate of interest. Knowing x is an integer, and the value doubles, and rate of return is between 39 and 45, its easy to figure out that x = 2 months, and rate is 41%. But this doesn't tell is the principle or final amount. Insufficient.

2. For one month more the total amount would have been $2744. Since both time and rate and principle is unknown this doesn't lead us anywhere.
For example, at 100% rate of return, the principal would have been 2744/(2^x+1). But since x is not know, nor is the rate we can't do a thing.

Combine them, and you know the rate and the time and the final amount for 3 months. Easy to get the principle.

Hence (C).

scorer · Answer

Both statements sufficient to answer.
I'll go with 'C'

what is OA?

ywilfred · Answer

OA is C. :-D

A certain sum was invested in a high-interest bond for which

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