College Algebra
posted by LeAnn/I still need help please on .
Bayside insurance offers two health plans. Under plan A, Giselle would have to pay the first $60 of her medical bills, plus 25% of the rest. Under plan B, Giselle would pay the first $170, but only 20% of the rest. For what amount of mediacl bills will plan B save Giselle money? Assume she has over $170 in bills.
Giselle would save with paln B if she had more than $___ in bills.
Here is part of my notes to get started but I'm not getting it after about half way through.....
Plan A would pay $60+25%($60$170)=
Plan B would pay $170+20%($170$170)=
Cost of Plan B $170+0.20(x$170)
Cost of Plan A $60+0.25(x$170)
$170+0.20(x$170)<$60+0.25(x$170)
$170+0.20x(0.20)($170)<$60+0.25(0.30)($170)
(These are the first steps)

First of all, you made an error in Plan A,
should have been 60 + .25(x60)
by setting $170+0.20(x$170)<$60+0.25(x$60)
you are asking for what values of x is Plan B < Plan A
That is good, now let's continue
170+0.20(x170)<60+0.25(x60) .... everything is in $, so we divide out the $
170 + .2x  34 < 60 + .25x  15
136 + .2x < .25x + 45
136  45 < .25x  .2x
91 < .05x
1820 < x or
x > 1820
So you found that for expenses greater than $1820 Plan B is less than Plan A
let's check it, say x = $2000
Plan A: 60 + .25(200060) = 545
PLan B: 170 + .2(2000170) = 536
Checks out!