上一個冇人回. 我開多個. 係 Exploring Mathematics 2A 第4課既 Challenging Problem 第 4 條.
一個比賽有 10 條問題. 答岩左有 20 分. 答錯扣 10 分. 唔答扣 5 分. 咁有一隊拎左 25 分. 咁佢地一共答岩 同 答錯 同 唔答左幾多條 ?.
要 Formula. Step. Answer 係 : Corret: ? Wrong: ? No respons: ?
唔該大家. 星期一要交 hw 喇. thz
Exploring Mathematics F2 問題 ( 星期一要交功課喇 ).
2008-11-08 10:37 pm
回答 (1)
2008-11-12 11:11 pm
✔ 最佳答案
let x be Correctlet y be Wrong
let z be No respons
then eqt 1) x+y+z=10
eqt 2) 20x-10y-5z=25
from 1) z=10-x-y
sub into eqt 2)
we have 20x-10y-5(10-x-y)=25
=> 25x-5y=75
therefore we have two solutions because (according to eqt 1.) x<=1 and x>=5 are impossible
x=3, y=0, z=7
and
x=4, y=5, z=1
收錄日期: 2021-04-26 20:22:18
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081108000051KK01125