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數學題目...請幫忙回答
2014-12-10 3:02 pm
Susan spent $76 in the stationary stores to buy pens and pencils. Pen costed $5 each while pencils costed $3 each. She bought more pencils than pens and the number of pens he bought is exactly twice the difference between the numbers of pens and pencils she bought. How many pen and pencils did she buy?
回答 (2)
2014-12-10 3:44 pm
✔ 最佳答案
Let no. of pen = x and no. of pencil = y.5x + 3y = 76 ............(1)
x = 2(y - x) because y > x
x = 2y - 2x
2y = 3x ...........(2)
From (2) 3y = 9x/2, sub into (1)
5x + 9x/2 = 76
10x + 9x = 152
19x = 152
x = 152/19 = 8 = no. of pen.
From (2), y = 3x/2 = 24/2 = 12 = no. of pencil.
2014-12-10 9:36 pm
我認為功課還是自己做的好.
希望幫到你.
還希望不會有人為了幫人而淪為鎗手. 代做功課。
希望幫到你.
還希望不會有人為了幫人而淪為鎗手. 代做功課。
收錄日期: 2021-04-24 23:23:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20141210000051KK00014