What is the least square number that is exactly divisible by 4, 6, 10, and 15?
Show answer & explanation
Correct answer: A
Explanation
LCM of 4, 6, 10, and 15:
4 = 2²
6 = 2 × 3
10 = 2 × 5
15 = 3 × 5
LCM = 2² × 3 × 5 = 60
60 = 2² × 3¹ × 5¹
To form a square number, all powers must be even. Therefore, multiply by 3 and 5 once each.
Required number = 60 × 3 × 5 = 900