All Exams Test series for 1 year @ ₹349 only
Question

There is a question followed by two statements I and II :

Question :

If x and y are integers, can we find |x-y| uniquely?

I. x2 + y2 = 25

II. x2 - y2 = 7

Which one of the following options is correct?

This question was previously asked in
UPSC CAPF 2026 General Ability and Intelligence Question Paper (19-Jul-2026)
The correct answer is

The question cannot be answered even using any of the statements

Statement I: \(x^2+y^2=25\) has integer solutions (x, y) = (0, ±5), (±5, 0), (±3, ±4), (±4, ±3). These give |x − y| values such as 5, 1 and 7 depending on which pair is taken, so the value is not unique. Statement I alone is insufficient.

Statement II: \(x^2-y^2=7\), i.e., \((x-y)(x+y)=7\). The integer factor pairs of 7 give (x, y) = (4, 3), (4, −3), (−4, 3), (−4, −3), yielding |x − y| equal to either 1 or 7 depending on the pair. Statement II alone is also insufficient.

Combining both: solving \(x^2+y^2=25\) and \(x^2-y^2=7\) together gives \(x^2=16,\ y^2=9\), so x = ±4 and y = ±3. All four sign combinations satisfy both equations simultaneously (since only the squares are fixed), giving |x − y| equal to 1 for (4, 3) or (−4, −3), and 7 for (4, −3) or (−4, 3).

Even together, the two statements do not pin down a unique value of |x − y|. Hence, the question cannot be answered even using both statements together.

Was this answer helpful?

Similar Questions

  1. P, Q, R and S are four places. To travel from P to R, one travels via Q and to travel from P to S, one travels via both Q and R. Between P and Q, there are 3 routes; between Q and R, there are 4 routes; and between R and S, there are 5 routes. The time taken to travel through these routes is exhibited on the following chart in hours for a specific vehicle :

    RoutesBetween P and QBetween Q and RBetween R and S
    1212
    231.52
    3422.5
    4-23
    5--3.5

    How many possible routes are there if the journey takes exactly 7 hours?


Important Questions from Quant Based Puzzle

  1. A number is subtracted from 4 times of it and then, the number obtained is added to its (the resultant’s) next number. If this gives the answer as 91, what was the original number?

  2. When twice of a number added to 3 is multiplied by 5 and added to the number itself, it gives 158. What is the square of that number?

  3. In a class of 72 students, the number of boys is twice the number of girls. Find the number of boys.

  4. Two years ago, T was twice as old as P. P is thrice as old as R. In five years, P will be 29. What is the present age of T?

  5. When a number is added to its multiple of 5 and its square, the sum of these three numbers is 91. Find the number.

Need Expert Advice?
Upcoming Exams
UPSC IFoS
November 22, 2026
UPSC SO Steno
December 12, 2026
Test Series
UPSC CAPF img
UPSC
UPSC CAPF (Assistant Commandants) 2026 Mock Test Series
181 Tests 4 Tests Free
6310 Attempts
4.2(116)
English, Hindi
More Questions from UPSC CAPF

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App