Problems on H.C.F and L.C.M
Find the greatest number of four digits which when divided by 10, 15, 21 and 28 leaves 4, 9, 15 and 22 as remainders respectively?
The least number which when divided by 4,5,6,8 and 10 is the LCM of these numbers. But each time to get 3 as remainder, we have to add the remainder 3 to the obtained LCM.LCM of (4, 5, 6, 8, 10)+ 3=120+3=123
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.
EXAMIANS