Divisibility between 6000 and 8000
Problem
Prerna was trying to find the number between 6000 and 8000 that are exactly divisible by 40, 48, 60 and 72. How many maximum numbers can she find?
Options:
A) 2
B) 3
C) 5
D) 4
Solution
Find LCM of 40, 48, 60 and 72.
40 = 2³ × 5
48 = 2⁴ × 3
60 = 2² × 3 × 5
72 = 2³ × 3²
LCM = 2⁴ × 3² × 5 = 720.
Numbers between 6000 and 8000 divisible by 720: 6480 (720 × 9), 7200 (720 × 10), 7920 (720 × 11).
So there are 3 such numbers.