Find the length of the shortest string that can be cut into equal length each 20cm, 24cm and 25cm.
The question is a bit garbled, but
20 = 2^2 * 5
24 = 2^3 * 3
25 = 5^2
So the LCM is 2^3 * 3 * 5^2 = 600
20 = 2^2 * 5
24 = 2^3 * 3
25 = 5^2
So the LCM is 2^3 * 3 * 5^2 = 600