Question

If Abhishek travels at a speed of 25 km/hr in his car he reaches his office 4 minutes late.If he drives at a speed of 30 km/hr he reaches 10 minutes early.Find the distace between his office and his home.

Answer 1

let.....x be required distance.
x/s=t...........
now
by 1 st condition...
x/25=t+1/15...................................( 4 minutes=1/15 hours)
and by second equation
x/30=t-1/6
from above equations,
x/25 -1/15=x/30 +1/6
so
x=35 km
ans is 35 km

Answer 2

Let distance be x km
Time taken to reach office at 25kmph=(x/25)*60 minutes
Time taken to reach office at 30kmph =(x/30)*60 minute
As per question (x/25)*60-4=(x/30)*60 +10
                          ⇒ (60x-100)/25= 2x+10
                          ⇒  60x -100 = 50x + 250 
                          ⇒ 10x=350
                                   x=35 km