there's a 100 dollar stuck up 12 feet up a building and you buy a 15 foot ladder that can be safely leaned at a 60 degree angle, can you reach the bill?

No i cannot be safely leaned

10 hours




The break even point occurs when R(h) = C(h). In other words, when the revenue is the same as the cost.

R(h) = C(h)
20+45h = 5h^2-30
20+45h-20 = 5h^2-30-20
45h = 5h^2-50
45h-45h = 5h^2-50-45h
0 = 5h^2-45h-50
5h^2-45h-50 = 0
5(h^2-9h-10) = 0
5(h-10)(h+1) = 0
h-10=0 or h+1=0
h=10 or h=-1

Ignore the negative h value. Negative hours make no sense.

The only practical solution is h = 10

Therefore the break even point occurs when h = 10