Question #91114

1 Answer
Dec 21, 2016

#12.5km#

Explanation:

Let distance from house be #d#
Let correct time be #t#. Converting given time in hours.

Time taken is found from the equation
#"Time"="Distance"/"Speed" #

  1. When walking at #5kmph#
    Let the person take time #t_1" which is "t+10/60=d/5#
    #=>60t+10=12d# .......(1)
  2. In the second case, speed is increased by #1kmph#. Let the person take time #t_2#
    #t_2" is "t-15/60=d/6#
    #=>60t-15=10d# ......(2)

Subtracting equation (1) from (2) we get
#-15-10=10d-12d#
#=>2d=25#
#=>d=12.5km#