Multiple

[billyr]

If n is a multiple of 5 and n=p^2*q, where p and q are prime numbers, which of the following must be multiple of 25?

a)p^2

b)q^2

c)p^2*q^2

d)pq

e)q^3

Thanks

[x2suresh]

If n is a multiple of 5 and n=p^2*q, where p and q are prime numbers, which of the following must be multiple of 25?

a)p^2

b)q^2

c)p^2*q^2

d)pq

e)q^3

Thanks

n=p^2*q = 5k (p,q are prime numbers)
one of them must be 5. we don't know whether p=5 or q=5

p^2*q^2 --> ALWAYS MULTIPLE OF 25 (here it doesn't matter whether p=5 or q=5)

c

[welcome]

Say n=5k

as n=p^2 * q => 5K = p^2 * q (as p and q are prime, q should be 5, because k can not ve 5 otherwise 5K will make 5^2 but when you will make it equal to p^2 *q then q will be 1, which can not be 1 as a prime.)

so q^2 = 25 = > and B.

[welcome]

Can you please post the OA.