Question

I am not sure why but it is causing me grief: "John walked 10 miles on Saturday. He walked twice as fast on the second 5 miles of his walk than he walked on the first 5 miles of his walk. Which expression represents the time he spent walking? Let x = John's speed on the first half of his walk."

Answer 1

The total time spent in walking is
`\frac {15}{2x}`.

Explanation:

The speed is defined as the rate of change f distance or the ratio of the distance covered to the time taken.

Total distance covered by John = 10 miles

Let he walked with speed x for the first 5 miles and then he walked with speed 2 x for the second 5 miles.

Let the time spent for the first 5 miles is t' and for the second 5 miles is t''.

So,

`t'=(5)/(x)\\\\t''=(5)/(2x)`

The total time spent in walking is

`t = t'+ t''=(5)/(x)+(5)/(2x)\\\\t =\frac {15}{2x}`