Posted by jennifer on Thursday, September 25, 2008 at 9:05am.
regular rate = r
discount rate = (r-5)
number bought = n
number that would have been bought = (n+1)
so
210 = r n
and
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)(n+7)=0
n = 8
sorry
(n+7)(n-6) = 0
n = 6
check
r = 210/n = 35
r-5 = 30
n+1 = 7
30 * 7 = 210 check
thank you very much
HELP!!!!!I need a better explination.
HELP!!!!!I need a better explination.
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