Exactly 3 deposits have been made in a savings account and the amounts of the deposits are 3 consecutive...

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Source: Official Guide

Exactly 3 deposits have been made in a savings account and the amounts of the deposits are 3 consecutive integer multiples of $7. If the sum of the deposits is between $120 and $170, what is the amount of each of the deposits?

1) The amount of one of the deposits is $49
2) The amount of one of the deposits is $63

The OA is B

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BTGmoderatorLU wrote:
Fri Dec 25, 2020 10:21 am
Source: Official Guide

Exactly 3 deposits have been made in a savings account and the amounts of the deposits are 3 consecutive integer multiples of $7. If the sum of the deposits is between $120 and $170, what is the amount of each of the deposits?

1) The amount of one of the deposits is $49
2) The amount of one of the deposits is $63

The OA is B
Given: Exactly 3 deposits have been made in a savings account and the amounts of the deposits are 3 consecutive integer multiples of $7. The sum of the deposits is between $120 and $170
STRATEGY: For questions like this in which we have a limited number of possible cases, I like to invest a little bit of time up front to list of all of those possible cases. This will typically make things much easier when analyzing the two statements.
Also, when I scan the answer choices, I see that two of the three deposits are $49 and $63. This will help me list the various cases


Since the sum of the deposits is between $120 and $170, the possible cases are:
case i: $49, $56, and $63 (sum = $168) [ since $168 is very close to the upper limit of $170, I can see that the remaining cases must start with smaller values than $49]
case ii: $42, $49, and $56 (sum = $147)
case iii: $35, $42, and $49 (sum = $126)
[s]case iv: $28, $35 and $42 (sum = $105) TOO small[/s]

Target question: What is the amount of each of the deposits?

Statement 1: The amount of one of the deposits is $49.
Check the three possible cases . . . i, ii and iii all apply, which means we can't answer the target question with certainty
Statement 1 is NOT SUFFICIENT

Statement 2: The amount of one of the deposits is $63.
Check the three possible cases . . . case i is the only one that satisfies statement 2, which means the three deposits are $49, $56, and $63
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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