2024 · Q42
Two towers A and B of height 23 m and 11 m respectively, stand 9 m apart. A straight rod is joined to the two tops of the towers. A monkey sitting on the top of A, climbs the rod to reach the top of B. If the monkey takes 5 minutes to reach the other end, what is the average speed of the monkey?
Elementary MathematicsTime, Speed and Distance
- A10 m/min
- B5 m/min
- C10 cm/sec
- D5 cm/sec
Explanation
The rod joins the tower tops, so its length is the hypotenuse of a right triangle with legs 9 m (horizontal gap) and 23−11 = 12 m (height difference): √(81+144) = 15 m. The monkey covers 15 m in 5 minutes, i.e. 3 m/min. Converting, 3 m/min = 300 cm/60 s = 5 cm/s — option D.