Question:
Find the least square number which is exactly divisible by each of the numbers 8, 12, 15 and 20.
Solution:
The smallest number divisible by each of these numbers is their L.C.M.
L.C.M. of 8, 12, 15, 20 = 120
Resolving into prime factors:
$120=2 \times 2 \times 2 \times 3 \times 5$
To make this into a perfect square, we need to multiply the number with $2 \times 3 \times 5=30$.
Required number $=120 \times 30=3600$