OG12 question

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OG12 question

by hk » Tue Jun 09, 2009 7:48 pm
Beginning in January of last year, Carl made deposits of $120 into his account on the 15th of each month for several consecutive months and then made withdrawals of $50 from the account on the 15th of each of the remaining months of last year. There were no other transactions in the account last year. If the closing balance of carl's account for May of last year was $2600, what was the range of the monthly closing balances of Carl's account last year?

(1) Last year the closing balance of Carl's account for April was less than $2625

(2) Last year the closing balance of Carl's account for June was less than $2675.


Can someone please explain to me how to solve this question. I'm having a hard time understanding the question. Now even of one deposits $120 on the 15th of every month for a year the balance by the end of the year would be $1440 much less than $2600 as per the question, let alone withdrawals!!! So is it that he already had some money in the account??
Your input would be deeply appreciated.

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Source: — Data Sufficiency |

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by abhinav85 » Tue Jun 09, 2009 7:58 pm
what is the OA?

According to me its E, because you really cant tell what are widhdrawal months in the last year.

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by vittalgmat » Tue Jun 09, 2009 10:53 pm
interesting problem.
I get C.
Read the problem carefully. It says that 120 was deposited for X consecutive months and then 50 was withdrawn in the next 12 -X consecutive months (ie till rest of the year).
So we need to find the month where depositing ended and withdrawal began.

May's closing balnce was 2600.

Lets now look at the stmts.

1. April's closing balance was < 2625. So try both deposit and withdrawals and see if it satisfies the stmt1.
a) deposit: if it was deposit, then April's closing balance would be
2600 - 120 = 2480, which is < 2625. This satisfies the stmt 1.
b) Withdrawal: This implies that April 's closing balnce was higher than May. ie. April = 2600 +50 = 2650. This does not satisfy stmt 1. So we will chose a).
Still we dont know when withdrawal started. so Insufficent.

2).June's closing balance was < 2675.
Again figure out what could it be. deposit or withdrawal.
it will be withdrawal. (try it out).
Still insufficient coz we dont know if June was the first month when withdrawl started. So not sufficient.

Together,
we know April-may was deposit and May-June was withdrawl. We know when withdrawl started. So we find the lowest (which is in december).
and highest, which is May.


So C.

Hope I havent missed anything

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by ketkoag » Wed Jun 10, 2009 12:22 am
the question has asked the range of monthly account balances, so u need to have account balance for all the months.. u don't need to calculate all those cos it is a DS problem but u have to make it sure that for how many months 120$ is added and for how many months 50$ are withdrawn.. and for this we need both the statements above to uniquely confirm about the transactions( added or withdrawn). I solved it the same way as vittalgmat did.. we need both the statements to get the range of account balances of all the months last year.. Hence C.

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by hk » Wed Jun 10, 2009 10:22 am
Vittalgmat - thanks a lot for taking the time to explain this question.. Great explanation. I think i was just over thinking on this question and yes the OA is C
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