Question

Q40 Which is the smallest square number that is divisible by each of the number 4,9 and10?
(a) 900 (b) 810 (c) 800 (d) 920

Answer 1

900 is the answer as it is smallest square number and divisible by 4 9 and 10

Answer 2

 Let us find LCM of 4, 9 and 10

4 = 2 x 2

9 = 3 x 3

10 = 5 x 2

So, LCM = 2 ² x 3 ² x 5 = 180

Now the LCM gives us a clue that if 180 is multiplied by 5 then it will become a perfect square.

The Required number = 180 x 5 = 900