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?
Aptitude
Calendar
Difficulty: Easy
Choose an option
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A27 seconds
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B36 seconds
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C30 seconds
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D33 seconds
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ENone of these
Answer
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