UPSC CAPF AC 2021 Paper

20 = 2× 2 × 5
24 = 2 × 2 × 2 × 3
30 = 2 × 3 × 5
LCM of 20, 24 and 30 = 2 × 2 × 2 × 3 × 5 = 120
Firstly number greater than 10000 which divisible by 120
= n × 120
= 84 × 120 = 10080
∴ Required number = 10080 - 10000 = 80