A monkey climbs an electric pole 12 m high. In the first minute he climbs 2 m and in the next minute he slides down 1 m. If this sequence continues, in how many minutes will the monkey climb to the top of the pole?

Question

Question

This question was previously asked in

UKPSC Lower PCS Preliminary Exam Official Paper (Held On: 11 May, 2025)

Answer 1

Given:

Height of the pole = 12 m

Climbing rate per minute = 2 m

Sliding rate per minute = 1 m

Formula Used:

Effective height climbed per 2 minutes = Climbing rate - Sliding rate

Total time = Time taken to reach effective height + Time taken for last climb

Calculation:

Effective height climbed per 2 minutes = 2 - 1 = 1 m

Total height reached before the last climb = Height of the pole - Last climb distance

Total height reached before the last climb = 12 - 2 = 10 m

Number of 2-minute cycles required = Total height reached before the last climb / Effective height climbed per 2 minutes

⇒ Number of 2-minute cycles = 10 / 1 = 10 cycles

Time for 10 cycles = 10 × 2 = 20 minutes

Time for the last climb = 1 minute

Total time = Time for 10 cycles + Time for the last climb

⇒ Total time = 20 + 1 = 21 minutes

The monkey will climb to the top of the pole in 21 minutes.