At sunrise two old women started to walk towards each other. one started from point a and went towards point b while the other started at b and went towards a. they met at noon but did not stop; each one continued to walk maintaining her speed and direction. the first woman came to the point b at 4: 00 pm, and the other one came to point a at 9: 00pm. at what time did the sun rise that day?

Let the distance between points a and b = d

For the women starting from a her velocity be and for the women starting from b her velocity be

Let the rising time of sun = x AM

We have   =

and we also have   =

At they meet means, they both travel a combined distance of d

So we have  

Substituting velocity values we will get

 x= 6 AM or 18 AM, but 18 AM is not possible,

Sun rise time is 6 AM

there are no contact forces mentioned on the list of choices that you've provided.