GRE
Exam
Numerical Ability
Arithmetic
If 3 is the GCD of +ve integers r, s which of the following could be GCD of 2r, 3s?
option
A. 3
B. 6
C. 9
D. 12
E. 18
Read Solution (Total 3)
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- ans:3 suppose we take a example 6 and 27 and its gcd is 3 then we multipli by 2 and 3 to 6 and 27 the result are 12 and 81 its gcd is also 3 so
- 11 years agoHelpfull: Yes(3) No(0)
- Let r=3m and s=3n where m and n are co-primes.
∴2r=6m and 3s=9n.
∵(m,n)=1
∴(6m,9n)=(6,9)=3
Where (x,y) denotes the GCD of x and y - 11 years agoHelpfull: Yes(0) No(0)
- The possible solutions are 3 & 9
If we choose (r,s)=(15,9) then (2r,3s)=(2*3*5,3*3*3)
then option is 3
If we choose (r,s)=(9,15) then (2r,3s)=(2*3*3,3*3*5)
then option is 9
- 11 years agoHelpfull: Yes(0) No(0)
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