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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