A women and her dog are out for a morning run to the river, which is located 4.0 km away. The women runs at 2.5 m/s in a straight line . The dog is unleashed and runs back and forth at 4.5 m/s between his owner and the river, until the women reaches the river . What is the total distance run by the dog?

7.2 km

Explanation:

Find the total distance that dog is running by

and use the time above that woman is taking to reach the river,

                                      t =

so,

plug the values You will get the answer.

a and b sometimes have a positive value

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.