I have a question:
Donna has three types of coins: $1 coins , $2 conins 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.(Answer in Algebraic equation)(process and construction)
數學的問題!!!!!!!!!!!!!!!!!!!!!!!!!!
2007-10-05 3:25 am
回答 (2)
2007-10-05 3:57 am
✔ 最佳答案
Let a be the number of $2 coins. *** number of $1 coins=3a
***number of $2 coins=a
***number of $5 coins=a-5
3a x 1 + 2 x a + 5 (a-5) = 325
3a +2a +5a -25 =325
10a = 350
a= 35
So, the number of $2 coins is 35, the value of $2 coins is 35 x2= $70
So, the number of $1 coins is 35 x3= 105, the value of $1 coins is 105x 1= $105
So, the number of $5 coins is 35-5= 30, the value of $5 coins is 30x 5= $150
$70+ $105+ $150= $325
參考: mine
2007-10-05 4:27 am
Let she has x $2 coins
Let she has 3x $1 coins
Let she has (x-5)$5 coins
2x+1(3x)+5(x-5)=325
2x+3x+5x-25=325
10x=325+25
10x=350
x=35
So she has 35 $2 coins.
Let she has 3x $1 coins
Let she has (x-5)$5 coins
2x+1(3x)+5(x-5)=325
2x+3x+5x-25=325
10x=325+25
10x=350
x=35
So she has 35 $2 coins.
參考: my kownledge
收錄日期: 2021-04-13 13:45:01
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