ardz24 wrote:From May 1 to May 30 in the same year, the balance in a checking account increased. What was the balance in the checking account on May 30?

(1) If, during this period of time, the increase in the balance in the checking account had been 12 percent, then the balance in the account on May 30 would have been $504
(2) During this period of time, the increase in the balance in the checking account was 8 percent.

What's the best way to determine whether statement 1 is sufficient? Can any experts help?

(1) If during this period of time, the increase in the balance in the checking account had been 12 percent, then the balance in the account on May 30 would have been $504.

=> Balance on May 1 = 504*[100 / (100 + 12)] = a finite amount; no need to calculate as of now. This will give balance on May 1, but we cannot get the balance on may 30. Insufficient.

(2) During this period of time, the increase in the balance in the checking account was 8 percent.

Clearly insufficient

(1) and (2) together

From (1), we have balance on May 1, say it is $x (a finite amount), thus, balance on may 30 = $x*(100 + 8)% = 1.08x = A finite amount.

This is a DS question and there is no need to compute the actual value if you are sure of getting the unique value.

The correct answer: C

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: Pasadena | Warsaw | Cairo | Kuala Lumpur | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.