Question

what is the HCF and LCM of two prime numbers A and B three alarm clock night at intervals of 69 15 minutes respectively if they start ringing together after what time will the next ring together​

Answer 1

Step-by-step explanation:

1)hcf of 2 prime no.s, a and b = 1

lcm of 2 prime no.s, a and b = ab

2) the three clocks will ring again together after lcm ( 6, 9 , 15)

i.e . after 90 mins.