What is the least number of soldiers that can be drawn up in troops of 10, 12, 15, 18, and 20 soldiers, and also in the form of a solid square?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 900.
The factors are as follows:
⇒ 10 = 5 × 2
⇒ 12 = 2 × 2 × 3
⇒ 15 = 3 × 5
⇒ 18 = 2 × 3 × 3
⇒ 20 = 2 × 2 × 5
Hence, LCM (12, 10, 15, 18, 20) = 180
Since the LCM = 180 is not a perfect square, we make it a perfect square by multiplying 5 (which is the least value to be multiplied)
Then 180 × 5 = 900 = 302
Therefore, 900 soldiers can be drawn up as a square.