數學問題..急 - Ans.fyi 參考答案

數學問題..急

用戶35372

2006-11-10 6:45 am

26. Donna has three types of coins:$1coins,$2coins and $5coins.the number of $1coins is three times that of $2coins.The number of $2 is 5 more than $5coins.The tatol value of Donna's coins is $325.How many $2coins does she have?

27. A load of 77kg is distributed among Alex,Ben and Curtis,so that Alex carries 1over3 of what Ben carries,and Ben carries twice as much as Curtis.What is the weight of the load that Ben carries?

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回答 (1)

myisland8132

2006-11-10 6:53 am

✔ 最佳答案

26 Donna has three types of coins; $1 coins,$2 coins and $5 coins. The number of $1 coins is three times that of $2 coins. The number of $2 coins is 5 more than the number of $5 coins. The total value of Donna's coins is $325. How many $2 coins does she have?
設她有 $5 有x個
則 $2 有x+5個
$1 有 3(x+5)
依題意
5x + 2(x+5) + 3(x+5) = 325
5x + 2x+10 + 3x+15 = 325
10x = 300
x = 30
所以
$5有30個
$2有30 + 5 = 35個
$1有 3*35 = 105個
(27) Assume that Curtis carry 3x kg,
then Ben carries twice as much as curtis, which is 6x kg
Alex carries 1/3 of what ben carries, which is 2x...

therefore 3x + 6x + 2x = 77kg
11 x = 77kg
x = 7kg

Ben carries 6x, which is 42 kg

參考: http://hk.knowledge.yahoo.com/question/?qid=7006102304312;http://hk.knowledge.yahoo.com/question/?qid=7006101603303

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