Posted by jennifer on Thursday, September 25, 2008 at 9:05am.
Furnace repairs
A repairman purchased several furnace blower motors for a total cost of $210. If is cost per motor had been $5 less, he could have purchased one additional motor. How many motors did he buy at the regular rate?
Please help

MATH  Damon, Thursday, September 25, 2008 at 9:30am
regular rate = r
discount rate = (r5)
number bought = n
number that would have been bought = (n+1)
so
210 = r n
and
210 = (r5)(n+1) = r n + r  5 n 5
from the first equation r = 210/n
then the second
215 = (210/n)n +210/n 5 n
5 = 210/n 5 n
5 n = 210 5 n^2
n^2 + n  42 = 0
(n8)(n+7)=0
n = 8

sorry factored wrong  Damon, Thursday, September 25, 2008 at 9:35am
sorry
(n+7)(n6) = 0
n = 6

MATH  Damon, Thursday, September 25, 2008 at 9:36am
check
r = 210/n = 35
r5 = 30
n+1 = 7
30 * 7 = 210 check

MATH  jennifer, Thursday, September 25, 2008 at 9:39am
thank you very much

MATH  Nathen, Wednesday, February 16, 2011 at 12:07am
HELP!!!!!I need a better explination.
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