Question

Nitin walks at 3/4 of his usual speed and reaches his home 10 minutes late ,find the usual time taken by him to reach his home ?

Answer 1

Let the usual speed of Nitin be "x" km/hrs
And let the distance be a constant "d" km
Finally let usual time taken be "t" min
Now as speed = distance / time
we have                                    x = d / t                   -------> eq 1
and also                                    3*x / 4 = d / t + 10 
hence by cross multiplication    x = 4*d/ 3*t + 30    --------> eq 2
equating 1 and 2 we get
4*d / 3*t + 30 = d / t
4dt = 3dt + 30d
dt = 30d
hence
t = 30
as t was assumed in minutes
His usual time is 30 minutes

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