Mabel pays $54 for N stickers. If the price of each sticker is increased by $1,
she can only buy (N-2) stickers by paying $10 more. Find the value of N.
F5 Maths
2010-09-06 12:20 am
回答 (2)
2010-09-06 12:26 am
✔ 最佳答案
New price for each = $ (54+10) / (N-2) Old price for each = $ 54/NSo(54+10)/(N-2) - 54/N = 164N - 54(N-2) = N(N-2)10N + 108 = N^2 - 2NN^2 - 12N - 108 = 0(N - 18)(N + 6) = 0N = 18 or N = - 6 (rejected)
2010-09-06 12:28 am
$54 for N stickers,
so,
$54 / N for a sticker
If, each sticker increased $1,
the price is $(54 / N + 1)
and pay $(54 + 10) = $64
So,
(54 / N + 1)(N - 2) = 64
54 + N - 108 / N - 2 = 64
N - 108 / N - 12 = 0
N^2 - 12N - 108 = 0
(N - 18)(N + 6) = 0
N = 18 or -6(rej.)
So, the value of N is 18
2010-09-05 16:28:42 補充：
F5 maths?? I don't think so.........
just S3~S4
so,
$54 / N for a sticker
If, each sticker increased $1,
the price is $(54 / N + 1)
and pay $(54 + 10) = $64
So,
(54 / N + 1)(N - 2) = 64
54 + N - 108 / N - 2 = 64
N - 108 / N - 12 = 0
N^2 - 12N - 108 = 0
(N - 18)(N + 6) = 0
N = 18 or -6(rej.)
So, the value of N is 18
2010-09-05 16:28:42 補充：
F5 maths?? I don't think so.........
just S3~S4
收錄日期: 2021-04-21 22:14:00
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