Maths 問題!!!!請高人教導。謝謝!

👨🏻‍🏫 學術台數學

[匿名]

2010-07-13 7:40 am

問題關於 Linear Equation in two unknowns.

Prudy spends $89 on buying some hamburgers and sundaes in a fast food shop. The numbers of hamburgers and sundaes are x and y respectively, which has a sum of 9. If the price of a hamburger and a sundae are $11 and $6 respectively, find the values of x and y.

請高人教導。謝謝!

更新1:

Help help !!!

回答 (2)

用戶2053

2010-07-13 7:52 am

✔ 最佳答案

The numbers of hamburgers and sundaes are x and y respectively, which has a sum of 9 , so
x + y = 9.....(1)
Prudy spends $89 , so
11x + 6y = 89.....(2)
(1) * 11 - (2) :
(11x + 11y) - (11x + 6y) = 9*11 - 89
5y = 10
y = 2 ,
sub it to (1) :
x+2 = 9
x = 7

👍 0 👎 0

michelle

2010-07-13 7:54 am

There are 2 equations here:
1. x + y = 9 ---------------------(1)
2. 11x + 6y = 89--------------(2)

(1): x + y = 9
y = 9 - x ----------------(3)

Subst. (3) into (2):
11x + 6y = 89
11x + 6(9-x) = 89
11x + 54 - 6x=89
5x = 35
x = 7

Subst. x = 7 into (3)
y= 9 - x
= 9 - 7
=2

Therefore, Prudy bought 7 hamburgers and 2 sundaes.

參考: my own knowledge

👍 0 👎 0

收錄日期: 2021-04-21 22:13:04
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100712000051KK01939

檢視 Wayback Machine 備份