Sam had a number of $1 and $5 coins. It was known that half the number of $1 coins was greater than the number of $5 coins by 2. If the total value of the coins was $32, how many $1 coins and how many $5 coins did Sam have?
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數學問題(方程式 f.1數)應用題
2006-10-20 1:44 am
回答 (5)
2006-10-20 1:55 am
✔ 最佳答案
No. of $5 coins = XNo. of $1 coins = 2 (X + 2)
5X + 2 (X + 2) = 32
7X = 28
X = 4
No. of $5 coins = 4
No. of $1 coins = 2 (4+2) = 12
2006-10-21 1:45 am
No. of $5 coins = X
No. of $1 coins = 2 (X + 2)
5X + 2 (X + 2) = 32
7X = 28
X = 4
No. of $1 coins = 2 (X + 2)
5X + 2 (X + 2) = 32
7X = 28
X = 4
2006-10-20 1:57 am
let x be the number of $1 coins
let y be the number of $5 coins
1/2x=y+2 -------(1)
1x+5y=32 -------(2)
(1)*2 : x=2y+4 -----(3)
(2)-(3):5y=32-4-2y
7y=28
y=4
sub y=4 into (3)
x=2(4)+4
x=12
所以Sam had 12 $1 conis and 4 $5coins
let y be the number of $5 coins
1/2x=y+2 -------(1)
1x+5y=32 -------(2)
(1)*2 : x=2y+4 -----(3)
(2)-(3):5y=32-4-2y
7y=28
y=4
sub y=4 into (3)
x=2(4)+4
x=12
所以Sam had 12 $1 conis and 4 $5coins
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2006-10-20 1:54 am
Let x and y be the number of $1 coins $5 coins respectively.
x + 5 y = 32 ----------( 1 )
1 / 2 x - 2 = y -----------( 2 )
Sub ( 2 ) into ( 1 ),
x + 5 ( 1 / 2 x - 2) = 3 2
x + 5 /2 x = 4 2
7 / 2 x =4 2
x = 12 ---------( 3 )
Sub ( 3 ) into ( 1 )
12 +5 y = 3 2
5 y = 2 0
y = 4
Sam have 12 $1 coins and 4 $5 coins.
x + 5 y = 32 ----------( 1 )
1 / 2 x - 2 = y -----------( 2 )
Sub ( 2 ) into ( 1 ),
x + 5 ( 1 / 2 x - 2) = 3 2
x + 5 /2 x = 4 2
7 / 2 x =4 2
x = 12 ---------( 3 )
Sub ( 3 ) into ( 1 )
12 +5 y = 3 2
5 y = 2 0
y = 4
Sam have 12 $1 coins and 4 $5 coins.
2006-10-20 1:47 am
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