Answered

a man walks from his  house to his daught's school at a speed of 3km/hr and returs at speed of 4 km/hr.if he takes 21 minutes for the total journey, find the distance between his house and the school?

Answer :

kvnmurty
Let us say the distance to school from home is S km
time taken for going to school from home =  S/3 hours
time taken for retuning home = S /4 hours

Total journey time : S/3+S/4 = 7S/12  hours
            given    this is   =  21 minutes  = 21 / 60 hours
So 7 S / 12  =  21 /  60
 S =  21 * 12 / 60 * 7  = 0.6 km  = 600 meters

Other Questions