If 10 spiders can catch 10 flies in 10 minutes (all working at the same constant rate), how many flies can 200 spiders catch in 200 minutes?

Difficulty: Easy

Correct Answer: 4000

Explanation:


Introduction:
Catching flies here scales with the number of spiders and with time, assuming a constant per-spider catch rate. We infer the rate from the base scenario and then scale to the larger numbers using direct proportionality (spiders × minutes × rate per spider-minute).


Given Data / Assumptions:

  • 10 spiders catch 10 flies in 10 minutes.
  • All spiders have the same constant efficiency.
  • Find flies caught by 200 spiders in 200 minutes.


Concept / Approach:
Let r be the number of flies caught by one spider per minute. Then total flies = spiders × minutes × r. Using the base case we find r, then apply it to the new case by multiplication without rounding since values are exact here.


Step-by-Step Solution:

Base: 10 = 10 * 10 * r → r = 10 / 100 = 0.1 flies per spider-minute New: Flies = 200 * 200 * 0.1 = 4000


Verification / Alternative check:
Proportion method: New/Base = (200/10) * (200/10) = 20 * 20 = 400. Then 10 * 400 = 4000, same result.


Why Other Options Are Wrong:
2000, 3000, 5000, 2500 are not consistent with the direct quadratic scaling in spiders and minutes based on the stated rate.


Common Pitfalls:
Treating the relationship as linear in one factor only (either spiders or minutes). The catch count scales with both.


Final Answer:
4000

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