A clock takes 9 seconds to strike 4 times. Assuming equal intervals between strikes, how long will it take to strike 12 times at the same rate?

Difficulty: Easy

Correct Answer: 33 seconds

Explanation:

Introduction / Context:Striking counts involve intervals between strikes. n strikes have (n − 1) intervals. If the interval length is known, time for any other number of strikes scales with interval count.

Given Data / Assumptions:

  • 4 strikes → 3 equal intervals → total 9 s.
  • Same striking rate for 12 strikes.

Concept / Approach:Interval length = 9 / 3 = 3 s. For 12 strikes, intervals = 11 → time = 11 * 3.

Step-by-Step Solution:Time for 12 strikes = 11 * 3 = 33 seconds.

Verification / Alternative check:Check proportionality with small cases; logic holds.

Why Other Options Are Wrong:27, 30, 36 assume wrong interval counts or mis-scale the base time.

Common Pitfalls:Using n instead of (n − 1) intervals.

Final Answer:33 seconds

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