A child goes to play with some pebbles in his bag The number of pebbles is such that he can ar...........

Explanation:

We need the least number, which means we must first find LCM of 18, 10 and 15
∴ LCM = 3 x 2 x 5 x 3 = 90
90 is not a perfect square.
90 = 3 x 3 x 2 x 5
Here there are two 3's (this gives square of 3) but only one 2 and one 5
If we multiply by 2 and 5 then we get, 3 x 3 x 2 x 2 x 5 x 5 = 900
900 is perfect square = number of marbles