雞兔同籠數學問題
回答 (2)
2010-01-14 4:08 am
✔ 最佳答案
設10元人民幣有y張，則5元人民幣y張，2元硬幣有(80-y-y)張10y+5y+2(80-y-y)=380
15y+160-2y-2y=380
15y-2y-2y=380-160
11y=220
y=220/11(約簡)
y=20
答:10元和5元人民幣有20張，2元人民幣有80-20-20=40張
2010-01-13 20:12:09 補充：
驗算:
10x20+5x20+2x(80-20-20)=380
希望幫到你，我做呢d題目做到好熟lu，有唔明就問我la^^
參考: 我本人
2010-01-14 2:54 am
2a+5b+10c=380 ...[1]
a+b+c=80...[2]
b=c ...[3]
put [3] to [2], a=80-2c ...[4]
put [3],[4] to [1], 160-4c+5c+10c=380, c=20, so b =20
put c,b=20 to [2] , a+20+20=80, a=40
right?
a+b+c=80...[2]
b=c ...[3]
put [3] to [2], a=80-2c ...[4]
put [3],[4] to [1], 160-4c+5c+10c=380, c=20, so b =20
put c,b=20 to [2] , a+20+20=80, a=40
right?
收錄日期: 2021-04-13 17:02:32
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100113000051KK01192