Clock chiming puzzle — if it takes 7 seconds to strike 7, how long will it take to strike 10?

Introduction / Context:
Chiming problems involve counting intervals between strikes, not the number of strikes themselves. The total time depends on the number of gaps between chimes and the constant length of each gap.

Given Data / Assumptions:

• Time to strike 7 = 7 seconds.
• Number of intervals between 7 strikes = 6.
• Assume each interval is equal in length.

Concept / Approach:
Compute the duration of one interval from the first case. Then multiply by the required number of intervals for 10 strikes (which is 9 intervals). Do not mistakenly multiply by the number of strikes.

Step-by-Step Solution:

Verification / Alternative check:
Sketch the timeline: first chime at time 0, then 9 uniform gaps until the 10th chime. Length per gap matches the 7-chime scenario, giving 10.5 seconds overall.

Why Other Options Are Wrong:

• 7 seconds — corresponds to 6 intervals, not 9.
• 9 seconds — would require a shorter interval than given.
• 10 seconds — close, but not exact; the precise value is 10.5 seconds.

Common Pitfalls:
Multiplying by the number of strikes instead of intervals, or assuming linearity without establishing the gap length first.

Final Answer:
None of these (exact time = 10.5 seconds).