What is the least number of soldiers that can be drawn up in troops of 12, 15, 18 and 20 soldiers and also in form of a solid square?

900

400

1600

2500

In this type of question, We need to find out the LCM of the given numbers.

LCM of 12, 15, 18 and 20;

12=2×2×3;15=3×5;18=2×3×3;20=2×2×5;

Hence, LCM = 2×2×3×5×3

Since, the soldiers are in the form of a solid square.

Hence, LCM must be a perfect square. To make the LCM a perfect square, We have to multiply it by 5,

hence,

The required number of soldiers

= 2×2×3×3×5×5

= 900