14 There are 300 coins in a box. x of them are 50￠ coins and the rest are $2 coins. The total value of the coins is $270.
(a) Find the value of x.
(b) Hence, find the number of $2 coins in the box.
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一題代數題(20分)(急!!!!!!!!!)
2007-11-08 6:13 am
回答 (6)
2007-11-08 8:32 pm
✔ 最佳答案
(a) The number of $2 coins = (300 - x).0.5 * x + 2 * (300 - x) = 270
=> 0.5x + 600 - 2x = 270
=> 600 - 1.5x = 270
=> 1.5x = 600 - 270
=> x = 330 / 1.5
=> x = 220 ....... (i)
The value of x is 220.
(b) 300 - x = 300 - 220 = 80 ...... by (i)
The number of $2 coins in the box is 80.
2007-11-13 6:37 am
I think you all have miss a point in question B.
The coins are 2 dollars coins,so it should be:
300-220÷2
=80÷2
=40
So,the number of $2 coins in the box should be 40.
The coins are 2 dollars coins,so it should be:
300-220÷2
=80÷2
=40
So,the number of $2 coins in the box should be 40.
2007-11-09 2:19 am
a)0.5x+2(300-x)=270
0.5x+600-2x=270
1.5x=330
x=220
so,the value of x is$220
b)300-220
=80
so,the number of $2 coins in the box are 80
0.5x+600-2x=270
1.5x=330
x=220
so,the value of x is$220
b)300-220
=80
so,the number of $2 coins in the box are 80
參考: me
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