1. If 3a=4k, 7b=10k and 6c=5k, where k≠0, find a : b : c.
2.The total value of some $0.5, $1.5 and $3 stamps is $73. It is known that the numbersof these three kinds of stamps are in the ratio of 4 : 9 : 7.
(a) If there are 4k pieces of $0.5 stamps, express the numbers of $1.5 stamps and $3 stamps in terms of k.
(b) Hence, find the number of $0.5 stamps.
急~急~急~Maths 3题
2008-05-05 1:34 am
回答 (5)
2008-05-05 1:52 am
✔ 最佳答案
1.If 3a=4k, 7b=10k and 6c=5k
then a = 4k/3 , b = 10k/7 , c = 6k/5
a:b:c = 4/3 : 10/7 : 6/5
a:b:c = 2/3 : 5/7 : 3/5
a:b:c = 70 : 75 : 63
2(a)
three kinds of stamps are in the ratio of 4 : 9 : 7
∴If there are 4k pieces of $0.5 stamps
The number of $1.5 stamps and $3 stamps are 9k and 7k respectively
(b)
total value of some $0.5, $1.5 and $3 stamps is $73
∴(0.5)(4k) + (1.5)(9k) + (3)(7k) = 73
36.5k = 73
k = 2
∴the number of $0.5 stamps = 2(4) = 8
2008-05-05 2:13 am
2008-05-05 2:05 am
1ans 15:14:24通分=20k慢慢計
2 ans
a,y,x$0.5, $1.5 and $3 stamps
0.5x+1.5y+ 3a=73
x+y+a=20
解方程有排計
2 ans
a,y,x$0.5, $1.5 and $3 stamps
0.5x+1.5y+ 3a=73
x+y+a=20
解方程有排計
參考: 我
2008-05-05 2:02 am
1.
a=4/3k b=10/7k c=5/6k
a:b:c
=4/3:10/7:5/6
=(4/3:10/7:5/6)*42
=56:60:35
2.
a.
4k*0.5+9k*1.5+7k*3=73
2k+13.5k+21k=73
36.5k=73 k=2
$1.5 stamps=9k=18 pieces
$3 stamps=7k=14 pieces
b.
k=2
4k=8
$0.5 stamps=8 pieces
a=4/3k b=10/7k c=5/6k
a:b:c
=4/3:10/7:5/6
=(4/3:10/7:5/6)*42
=56:60:35
2.
a.
4k*0.5+9k*1.5+7k*3=73
2k+13.5k+21k=73
36.5k=73 k=2
$1.5 stamps=9k=18 pieces
$3 stamps=7k=14 pieces
b.
k=2
4k=8
$0.5 stamps=8 pieces
2008-05-05 1:48 am
Can you say Chinese...............=.=?
收錄日期: 2021-04-13 15:30:48
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https://hk.answers.yahoo.com/question/index?qid=20080504000051KK02225