Question

A man covers a distance of 1200 km in 70 days resting 9 hours a day, if he rests 10 hours a day and walks with speed 1½ times of the previous in how many days will he cover 840 km ?
A) 39 days
B) 37 days
C) 35 days
D) 33 days

Answer 1

Distance d = 1200km
let x be the speed

he walks 15 hours a day(ie 24 - 9)... so totally he walks for 1050hrs...

x = 1200/1050 => 120/105 = 24/21 => 8/7kmph


given 1 1/2 of prev speed
so 3/2 * 8/7= 24/14 = 12/7

new speed = 12/7kmph

now he rests 10 hrs a day ... means he walks 14 hrs a day...

time = 750 * 7 /12 => 437.5hrs
=> 437.5/14 = 31.25

so he ll take 31.25 days to cover 750km

Answer 2

Distance d = 1200km
let x be the speed

he walks 15 hours a day(ie 24 - 9)... so totally he walks for 1050hrs...

x = 1200/1050 => 120/105 = 24/21 => 8/7kmph


given 1 1/2 of prev speed
so 3/2 * 8/7= 24/14 = 12/7

new speed = 12/7kmph

now he rests 10 hrs a day ... means he walks 14 hrs a day...

time = 750 * 7 /12 => 437.5hrs
=> 437.5/14 = 31.25

so he ll take 31.25 days to cover 750km