A bus driver covers a certain distance in 3 hours at an average speed of 80 km/h. How long will the journey take at an average speed of 50 km/h?​

The ksp expression for the system pbcl2(s) pb+2(aq) + 2 cl-(aq) is: [pbc12][pb+2][2cl-] [pb+2][cl-]2 [pb+2][2cl-]2 [pbcl2][pb+2][cl-]2 [pb+2][2cl-]2[pbcl2]

The anwser cause i do not understand just plez

Factor and solve to find roots x squared -x - 90 =0