Shirley has three types of coins: $1-coins, $2-coins and $5-coins. The number of $5-coins is more than the number of $1-coins by 3, while the number of $2-coins is 8 more than twice the number of $5-coins. If Shirley has 97 coins altogether, find the total value of the coins.
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一條中一數學題~! HELP!!!!!
2007-11-29 2:06 am
回答 (4)
2007-11-29 2:56 am
✔ 最佳答案
Let x be the number of $1-coins,x+(x+3)+[2(x+3)+8]=97
2x+3+2x+6+8=97
4x+17=97
4x=80
x=20
Therefore,the value of the coins
=$1*20+$5*(20+3)+$2*[2(20+3)+8]
=$20+$115+$108
=$243
2007-11-29 2:33 am
Let y be the number of the $5-coins:
x-3+8+2x+x=97
4x-5=97
4x=92
x=23
then the total value of the coins=$1(23-3)+$2[8+(2x23)]+$5x23
=$243
2007-11-28 18:34:34 補充：
不好意思，頭一句的y應該是x
x-3+8+2x+x=97
4x-5=97
4x=92
x=23
then the total value of the coins=$1(23-3)+$2[8+(2x23)]+$5x23
=$243
2007-11-28 18:34:34 補充：
不好意思，頭一句的y應該是x
2007-11-29 2:15 am
你話???
2007-11-29 2:11 am
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你講中文我解答你啦
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https://hk.answers.yahoo.com/question/index?qid=20071128000051KK02150