How many integers between 4000 and 6000 are divisible by 32, 40, 48, and 60?

Difficulty: Medium

Correct Answer: 4

Explanation:


Introduction:
An integer divisible by multiple numbers must be a multiple of their least common multiple. We count how many multiples of that LCM lie in the specified interval.


Given Data / Assumptions:

  • Range: 4000 to 6000 inclusive
  • Divisors: 32, 40, 48, 60


Concept / Approach:
Compute LCM(32, 40, 48, 60). Then count multiples in the range using ceiling and floor division.


Step-by-Step Solution:

LCM = 480 Smallest multiple ≥ 4000: 9 * 480 = 4320 Largest multiple ≤ 6000: 12 * 480 = 5760 Values: 4320, 4800, 5280, 5760 Count = 4


Verification / Alternative check:
Each listed value is divisible by all four divisors by construction through the LCM.


Why Other Options Are Wrong:
2, 3, and 5 do not match the exact count of LCM multiples in the interval.


Common Pitfalls:
Taking pairwise divisibility instead of using the LCM, which can overcount or undercount.


Final Answer:
4

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