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When a certain positive integer P is divided by another positive integer, the remainder is $${r_{1}}$$ . When a second positive integer Q is divided by the same integer, the remainder is $${r_{2}}$$ and when (P + Q) is divided by the same divisor, the remainder is $${r_{3}}$$ . Then the divisor may be :

A. $${r_{1}}$$$${r_{2}}$$$${r_{3}}$$

B. $${r_{1}}$$ + $${r_{2}}$$ - $${r_{3}}$$

C. $${r_{1}}$$ - $${r_{2}}$$ + $${r_{3}}$$

D. $${r_{1}}$$ + $${r_{2}}$$ - $${r_{3}}$$

Answer: Option D

Solution(By Examveda Team)

Let P = x + $${r_{1}}$$ and Q = y + $${r_{2}}$$, where each of x and y are divisible by the common divisor.
Then, P + Q = (x + $${r_{1}}$$) + (y + $${r_{2}}$$)
                    = (x + y) + ($${r_{1}}$$ + $${r_{2}}$$)
(P + Q) leaves remainder $${r_{3}}$$ when divided by the common divisor.
⇒ [(x + y) + ($${r_{1}}$$ + $${r_{2}}$$) - $${r_{3}}$$] is divisible by the common divisor.
Since (x + y) is divisible by the common divisor, so divisor = $${r_{1}}$$ + $${r_{2}}$$ - $${r_{3}}$$

This Question Belongs to Arithmetic Ability >> Number System

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Comments ( 3 )

  1. Murali Krishna
    Murali Krishna :
    2 years ago

    I think there is a possibility that r1 + r2 - r3 is multiple of the common divisor, am i correct if not correct me with the reason.... please

  2. Kavya Hemanth
    Kavya Hemanth :
    2 years ago

    Why is it -r3 and not +r3

  3. Nirzor Talukder
    Nirzor Talukder :
    3 years ago

    Why cannot r1+r2-r3 be a multiple of the divisor?

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