a) Let m and n be non-zero number. If (3m+2n)/(m-n)=21/2, find m:n, find m:n
b) If rice of brand A costs $40/kg and rice of brand B costs $60/kg. Find the costs of a mixture of m kg of rice of brand A and n kg of rice of brand B.
rate and ratio?
2016-06-13 12:50 pm
回答 (1)
2016-06-13 2:42 pm
✔ 最佳答案
(a)(3m + 2n) / (m - n) = 21 / 2
21 (m - n) = 2 (3m + 2n)
21m - 21n = 6m + 4n
15m = 25n
3m = 5n
m/n = 5/3
m : n = 5 : 3
(b)
m : n = 5 : 3
Let m = 5k and n = 3k
Cost the mixture
= $(40m + 60n)/(m + n) kg
= $(40×5k + 60×3k)/(5k + 3k) kg
= $380k/8k kg
= $47.5/kg
收錄日期: 2021-04-18 15:07:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160613045000AArj5pb