Question

A cuckoo strikes at regular time intervals. It takes 10 seconds to strike at 6 o’clock. How many seconds will it take to strike at 10 o’clock?

• A. 10 seconds
• B. 15 seconds
• C. 16.7 seconds
• D. 16 seconds

Hint:

Read wording carefully: “regular time intervals” usually means equal gaps between chimes (model A). Some keys, however, treat it as equal time per chime.

Answer 1

The Correct Option is C

Two common interpretations:
(A) Equal \textbf{interval between chimes.} At 6 o’clock there are 6 chimes \(⇒\) 5 intervals \(=10\) s \(⇒\) interval \(=2\) s. For 10 o’clock: 9 intervals \(⇒ 18\) s. (Not listed.)
(B) Equal time per \textbf{chime.} Time per chime \(=\frac{10}{6}\) s \(⇒\) for 10 chimes \(=\frac{10}{6}\times 10=16.\overline{6}\) s \(\approx 16.7\) s.
Most exam keys assume model (B), giving option (c).