BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Data sufficiency

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 772
Joined: Wed Aug 30, 2017 6:29 pm
Followed by:6 members

Data sufficiency

by BTGmoderatorRO » Mon Sep 18, 2017 1:20 pm
If p is an integer and p* = p^2 + 2, what is the value of integer k?

(1) When k + 2 is divided by 5 the remainder is 2.
(2) 18 < k* < 35

a. only statement 1 is sufficient
b. Both statement are sufficient
c. statement 1 is not sufficient and statement 2 is sufficient
d. Both statement are not sufficient
e. statement 2 is sufficient

OA is d

express mathematically why option C is the right answer?
Top
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

by Jay@ManhattanReview » Mon Sep 18, 2017 11:26 pm
Roland2rule wrote:If p is an integer and p* = p^2 + 2, what is the value of integer k?

(1) When k + 2 is divided by 5 the remainder is 2.
(2) 18 < k* < 35

OA is d

express mathematically why option C is the right answer?
Either the question is wrong or it is not posted correctly.

Statement 1: When k + 2 is divided by 5 the remainder is 2.

k can have many values: 2, 7, 12, 17, 22, ... No unique value. Insufficient.

Statement 2: 18 < k* < 35

=> 18 < k^2 + 2 < 35

=> 16 < k^2 < 33

Since k is an integer, two values of k are eligible. k = ±5. No unique value of k. Insufficient.

Statement 1 & 2:

From Statement 1, we have k = 2, 7, 12, 17, ... and
From Statement 2, we have k = ±5.

We see that no value is common in both the statements, which is not possible. At least one value from each statement should be common.

An official DS question represents a holistic scenario. Statement 1 cannot invalidate Statement 2 and vice-versa. They must exist in sync.

Hope this helps!

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide

-Jay
__________________________________
Manhattan Review GMAT Prep

Locations: New York | Bangkok | Abu Dhabi | Rome | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Post new topic Post Reply
• Page 1 of 1