Problems on H.C.F and L.C.M
Six bells commence tolling together and toll at intervals of 2, 4, 6, 8 10 and 12 seconds respectively. In 30 minutes, how many times do they toll together ?
L.C.M. of 2, 4, 6, 8, 10, 12 is 120. So, the bells will toll together after every 120 seconds(2 minutes). In 30 minutes, they will toll together 30 + 1 = 16 times. 2
Perfect Square : A number when written as product of prime factors , if each prime factor has even number as its power , then the number is perfect square. Writing the given number as product of prime factors 6 = 2 x 3 12 = 2³ x 3 18 = 2 x 3² 24= 2³ x 3 LCM = 2³ x 3² = 72 But 72 is not the perfect square. But multiples of 72 are also exactly divisible by given numbers. 72 x 2 =144 is the perfect square.
The greatest number when divide 147,185 and 251 leaving the remainders 3,5 and 11.Means the greatest number is not exactly dividing the given numbers. If we subtract the remainders from the respective numbers, then they are exactly divisible by the greatest numbers. The required greatest number = HCF of (147 - 3),(185-5) and ( 251-11) =HCF of 144,180 and 240 =12
EXAMIANS