Please can you correct my exam preparation.

The frequencies in x(t) is 10 and 30. f=(20.pi)/(2.pi) and f=(60.pi)/(2.pi)

The digital frequencies are 10/65 and 30/65 which is k/N.

However for the fundamental frequency of x(t) is at GCD(10,30) = 10 Hz. One period of x(t) is then 1/30 s. The Greatest Common Denominator.

So the answer is 1. 10Hz.

Is this correct?

Regards

Joshy