What is the domain of the square root function graphed below?

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)

Talia took the bus from her home to the bank and then walked back to her home along the same route. the bus traveled at an average speed of 40 km/h and she walked at an average speed of 5 km/h. to determine the time, x, that it took talia to walk home, she used the equation 40(0.9 – x) = 5x. the time of trip 2 is hours. the distance of trip 1 is km.

What’s the answer? and how do i solve it ?