F1 數學題 - Ans.fyi 參考答案

F1 數學題

2012-12-10 9:48 pm

A tea party is held and the total expenditure will be shared equally among the participants.
If each participant pays $ 30, there is a lack of $30. If each pays $32, there will be an excess of $80.

a) Find the number of participants in the party.
b) How much is the total expenditure?

我唔明點計, 請提供詳細解釋,
解得我最明就係最佳答案, 謝謝

回答 (1)

James But

2012-12-10 10:26 pm

✔ 最佳答案

因為而家講緊人數同埋個支出係一個定數, 所以你可以將兩個情況寫曬出黎先.
先設定左兩個未知數先, 咁之後睇返題目, 佢話每人比30蚊, 都重差30蚊先可以收支平衡. 咁每人比32蚊, 又反而多左80蚊.
let X be number of particicpant
let Y be the total expenditure

咁好簡單每人比ge錢總和減去支出等於結果, 就寫到以下兩個情況
(1) 30X - Y = -30
(2) 32X - Y = 80

咁你是但係一條式到拎個x或者拎個y出黎. 睇題目要你計咩, 之後放入去拎一條式到令到佢得返一個未知數. 咁你就會計到其中一個答案出黎, Step 我就唔寫啦你自己應該識計.

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