What is the smallest perfect square number that is divisible by both 10 and 15 ?

900 360 1800 1200

900

L.C.M. of 10 , 15 = 30 = 2 x 3 x 5 30 must be multiplied by 2 x 3 x 5 to make it a perfect square. = 30 x 2 x 3 x 5 = 900  Method - 2, There is only one option that has a perfect square root so the answer will be 900 only.