Question

Question #91114

Answer 1

`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`