要有步驟
1)若3a=2b和4b=5c,求a:b:c
2)若3a=4b=5c,求a:b:c
3)若a分1:b分1=2:5和a分1:c分1=5:3,求a:b:c
4)若3a=4k,7b=10k和6c=5k,其中k不=0,求a:b:c
(先以k分別表示a,b,c的值)
5)現在一些面值$0.5 ,$1.5 和$3的郵票,總值$73,已知該三種郵票的數量之比是4:9:7
若面值$0.5的郵票有4k枚,試分別求面值是$1.5和$3的郵票數量,答案以k表示
b)由此,求面值$0.5郵票的數量
f.1 maths比和率(20分)快
2008-03-16 7:50 pm
回答 (3)
2008-03-16 8:22 pm
1. 3a=2b 4b=5c
a:b=2:3 b:c=5:4
a:b=10:15 b:c=15:12
a:b:c=10:15:12
2. 3a=4b=5c
3a=4b 4b=5c
a:b=4:3 b:c=5:4
a:b=20:15 b:c=15:12
a:b:c=20:15:12
3. 1/a:1/b=2:5 1/a/1/c=5:3
a:b=5:2 a:c=3:5
a:b=15:6 a:c=15:25
a:b:c=15:6:25
4. 3a=4k 7b=10k 6c=5k
a=4k/3 b=10k/7 c=5k/6
a:b:c=4k/3:10k/7:5k/6
=4/3:10/7:5/6
=56:60:35 (x42)
5. stamp with value$1.5 is 9k
stamp with value $3 is 7k
4kx0.5+9kx1.5+7kx3=73
2k+13.5k+21k=73
36.5k=73
k=2
the number of stamp with value of$0.5=4k=8
a:b=2:3 b:c=5:4
a:b=10:15 b:c=15:12
a:b:c=10:15:12
2. 3a=4b=5c
3a=4b 4b=5c
a:b=4:3 b:c=5:4
a:b=20:15 b:c=15:12
a:b:c=20:15:12
3. 1/a:1/b=2:5 1/a/1/c=5:3
a:b=5:2 a:c=3:5
a:b=15:6 a:c=15:25
a:b:c=15:6:25
4. 3a=4k 7b=10k 6c=5k
a=4k/3 b=10k/7 c=5k/6
a:b:c=4k/3:10k/7:5k/6
=4/3:10/7:5/6
=56:60:35 (x42)
5. stamp with value$1.5 is 9k
stamp with value $3 is 7k
4kx0.5+9kx1.5+7kx3=73
2k+13.5k+21k=73
36.5k=73
k=2
the number of stamp with value of$0.5=4k=8
2008-03-16 8:01 pm
1) a/b = 2/3 = 10/15 b/c = 5/4 = 15/12
a:b:c = 10:15:12
2) a/b = 4/3 = 20/15 b/c = 5/4 = 15/12
a:b:c =20:15:12
3) 1/a : 1/b = 2:5
(1/a)/(1/b) = 2:5
b/a = 2:5
a:b = 5:2 = 15:6
1/a : 1/c = 5:3
(1/a)/(1/c)=5:3
c/a = 5:3
a:c = 3:5 = 15:25
a:b:c = 15:6:25
4) k = 3a/4 = 7b / 10 = 6c/5
i.e. 3a/4 = 7b/10 = 6c/5
a:b = 14:15 = 56:60 b:c = 12:7 = 60:35
a:b:c = 56:60:35
5a) $1.5郵票的數量 = 4k x 9/4 = 9k
$3郵票的數量 = 4k x 7/4 = 7k
5b 0.5 x 4k + 1.5 x 9k + 3 x 7k = 73
k = 2
$0.5郵票的數量 = 2 x 4
= 8
a:b:c = 10:15:12
2) a/b = 4/3 = 20/15 b/c = 5/4 = 15/12
a:b:c =20:15:12
3) 1/a : 1/b = 2:5
(1/a)/(1/b) = 2:5
b/a = 2:5
a:b = 5:2 = 15:6
1/a : 1/c = 5:3
(1/a)/(1/c)=5:3
c/a = 5:3
a:c = 3:5 = 15:25
a:b:c = 15:6:25
4) k = 3a/4 = 7b / 10 = 6c/5
i.e. 3a/4 = 7b/10 = 6c/5
a:b = 14:15 = 56:60 b:c = 12:7 = 60:35
a:b:c = 56:60:35
5a) $1.5郵票的數量 = 4k x 9/4 = 9k
$3郵票的數量 = 4k x 7/4 = 7k
5b 0.5 x 4k + 1.5 x 9k + 3 x 7k = 73
k = 2
$0.5郵票的數量 = 2 x 4
= 8
2008-03-16 7:55 pm
a)3a=2b and 4b=5c,a:b:c
a:b:c=10:15:12
this only.
a:b:c=10:15:12
this only.
收錄日期: 2021-04-29 20:24:22
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080316000051KK00920