Question

What is the hcf of 2 to the power 315 -1 and 2 to the power 25 -1?

Answer 1

Explanation:

Correct option is

C

31

We know that the HCF of (a

m

−1) and (a

n

−1) is given by (a

HCF(m,n)

−1)

So let us first find the HCF of 115 and 25 by factorizing them as follows:

115=5×23

25=5×5

Therefore, the HCF(115,25)=5

Thus, the .HCF of (2

115

−1) and (2

5

−1) is given by (2

HCF(115,25)

−1) that is:

2

5

−1=32−1=31

Hence, the .HCF of (2

115

−1) and (2

5

−1) is 31.