Question

Find the least 5-digit number which is exactly divisible by 20, 25, 30.

Answer 1

Least five digit number = 10000

L.C.M. of 20,25,30 is 300.
But we want the least five digit number which is divisible by 20, 25, 30.
So, we will multiply the L.C.M. by a number that makes it the least five digit number divisible by 20, 25, 30.
300××31 = 9300
300××32 = 9600
300××33 = 9900
300××34 = 10200 
So, the least five digit number divisible by 20, 25, 30 is 10200.