manhattan gmat prep

[sickvick]

An investor purchased a bond for p dollars on Monday. For a certain number of days, the value of the bond increased by r percent per day. After this period of constant increase, the bond decreased the next day by q dollars and the investor decided to sell the bond that day for v dollars. When did the investor sell the bond if r= 100 (sqrt v+q/p) -1 (where 1 is not in the square root)

Wednesday of the same week.
Thursday of the same week.
Friday of the same week.
Monday of the next week.
Tuesday of the next week

[mamil]

I would go for A - Wednesday of the same week

- First hint is the sqrt... which indicates something was squared... and in the time value of money calculation only the time period is in the powers.. so two days.. which gives wednesday

- the full solution
the price after n days when it increases by r% each day is P(1+r)^n .. where n is number of days
- then the price goes down by Q which gives the price on (n+1)th day to be P(1+r)^n - Q
- at this price the bond is sold .. which is V
so the final equation is V= P(1+r)^n - Q

solving for r and comparing it with the given equation... n=2... which gives two days from Monday.. the Wednesday of the same week

[manish8109]

Discussed Before

http://www.urch.com/forums/gmat-prob...-interest.html (Compound Interest)

[mamil]

I stand corrected.. it is Thursday... Ans B
I failed to read the stem properly.. it is asking for the day it is sold