Question

If the tourist bus runs at 36 kmph and it reaches its destination late by 10 minutes but if it runs at 42 kmph it reaches its Destination 5 minutes late before the time find the distance to be covered by the bus

Answer 1

the tourist bus runs at 36 kmph and it reaches its destination late by 10 minutes

but if it runs at 42 kmph it reaches its Destination 5 minutes early before the time

NOW,

Let the distance to destination be x km

Time taken if he rides at 36 kmph = x/36 hr  [ T=D/S]                                        

Time taken if he rides at 42 kmph = x/42 hr    [ T=D/S]

Difference of time = 5 min + 10 min = 15 min = 1/4 hr

x/36−x/42=1/4

7x−6x=63

x=63

i.e., Distance to office = 63 km

Time taken if he rides at 36 kmph = 63/36 = 7/4 hr =105 mins

if he rides at 36 kmph, he will reach office 10 minutes late

Therefore, to reach office just in time,  he should reach in 95 minutes (or 1 hour 35 mins   =19/12 hrs )

Required speed =[D/T]  = 63/(19/12)=756/19=39.79 kmph   ANS