Hello, a sphere has zero vertices.
You are right ! It is 8.246 and so on ;)
You solve for x and get x<-2 or x>= -1/2 and then graph
Let the distance to his office be x, then
On monday, speed = x/20 miles per minutes = 3x miles per hour
On tuesday, speed = (3x + 15) miles per hour
Time = distance / speed
(20 - 6)/60 hours = x/(3x + 15) hours
7/30 = x/(3x + 15)
7(3x + 15) = 30x
21x + 105 = 30x
30x - 21x = 105
9x = 105
x = 105/9 = 11.7 miles
Therfore he travels an average of 11.7 miles to work.
It would need 288 cubes to fill up the prism.
