Posted by jennifer on Thursday, September 25, 2008 at 9:05am.
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?
MATH - Damon, Thursday, September 25, 2008 at 9:30am
regular rate = r
discount rate = (r-5)
number bought = n
number that would have been bought = (n+1)
210 = r n
210 = (r-5)(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
n = 8
sorry factored wrong - Damon, Thursday, September 25, 2008 at 9:35am
(n+7)(n-6) = 0
n = 6
MATH - Damon, Thursday, September 25, 2008 at 9:36am
r = 210/n = 35
r-5 = 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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