If Bob can paint the fence in 4 hours, then in 1 hour he gets 1/4 of the fence painted. If Sarah can paint the fence in 2.5 hours, then she gets 2/5 of the fence painted in one hour (1/2.5 = 2/5). We add those amounts together and set them equal to 1/x, x being the the total time it will take them to paint the whole fence. 1/4 + 2/5 = 1/x. Find a common denominator first, then add the left side together. 5/20 + 8/20 = 1/x. 13/20 = 1/x. Cross-multiply to get 13x = 20 and x = 1.54 hours, just a bit over an hour and a half.
The length of the pantry is 3 feet.
You start by dividing 81 by 9 since the pantry's area is 9 times the area of the whole kitchen. Then you divide the area of the pantry (which is 9 because 9 times 9 is 81) by 3 since length times width equals the area. You get 3 feet in the end.
Hope this helped :)
I am getting 7 as the value of b. I do not believe 4 is a correct answer!
Here's why:
General equation of a circle in the xy plane
with 
being the x,y coordinates of the center.
The center point can be determined from the two endpoints of the diameter because the line segment is horizontal, so we just find the center of the x coordinates of the two points:
and the radius r = diameter/2 = 8-(-2)/2 = 5
so we have
Given a point on the circle (0,b) with b>0:
What do you need help with?
