Find the smallest square number that is divisible by each of the numbers 8, 15 and 20

The correct option is B 3600

L.C.M. of 8, 15 and 20 is 120.

Prime factors of 120 = 2 x 2 x 2 x 3 x 5

Here, prime factors 2, 3 and 5 have no pair. Therefore 120 must be multiplied by 2 x 3 x 5 to make it a perfect square.

$\begin{array}{cc}\therefore 120\times 2\times 3\times 5& =240\times 15\\ & =3600\end{array}$

Hence, the smallest square number which is divisible by 8, 15 and 20 is 3600.