Question

A mountaineer climbed (71 + 3/7)% of the height of a mountain in 9 hours and in the next one hour, he covered 12.5% of the remaining height. if the height of the mountain is 2688 m, then the time he will take to climb 384m at the speed equal to the speed in the 10th hour is.
1. 4 hr
2. 7 hr
3. 3 hr
4. 6 hr

Answer 1

Correct Answer - Option 1 : 4 hr

GIVEN:

Height climbed in 9 hrs = (71 + 3/7)%

Height climbed in 10th hour = 12.5% of remaining

Height of mountain = 2688 m

Height to climb = 384 m 

FORMULA USED:
Speed = Distance/Time

CALCULATION:

Distance in 9 hrs =(71 + 3/7)% = 5/7

Remaining distance = 1 - 5/7 = 2/7

Also, 12.5% = 1/8

Distance in 10th hour = 1/8 × 2/7 = 1/28 of total 

Required distance = 1/28 × 2688 = 96 m

Speed in 10th hr = 96 m/h

Time to climb 384 m = 384/96 = 4 hr

∴ The answer will be 4 hr.