# F.2 ratio 文字題，help~!!!!!

John shares 100 marbles with Jack in the ratio 1 : 3. Jack then gives 45 of his marbles to Joseph. Find the ratio of John's number of marbles to that of Jack to that of Joseph.

Mary has 28 \$5-coins, some \$2-coins and some \$0.5-coins. If the ratio of the value of \$5-coins to that of \$2-coins to that of \$0.5-coins is 35 : 24 : 11, find

(a) the number of \$ 2-coins Mary has,

(b) the ratio of the number of \$5-coins to \$2-coins to \$0.5-coins

### 4 個解答

• 最愛解答

John shares 100 marbles with Jack in the ratio 1 : 3.

so, John has 25 and Jack has 75

Jack then gives 45 of his marbles to Joseph.

so, Jack has 30 and Joseph has 45

the ratio of John's number of marbles to that of Jack to that of Joseph.

= 25 : 30 : 45

= 5 : 6 : 9

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2012-01-05 20:06:08 補充：

well...since someone copied my answers before and finally got the "best answer", i don't know this happen again.

2012-01-06 18:26:21 補充：

(a) let Mary has k \$2-coins

28*5 : k*2 = 35 : 24

140 : 2k = 35 : 24

70 / k = 70 / 48

k = 48

2012-01-06 18:29:54 補充：

(b) let Mary has n \$0.5-coins

28*5 : 48*2 : n*0.5 = 35 : 24 : 11

140 : 96 : 0.5n = 140 : 96 : 44

0.5n = 44

n = 88

ratio of the number of \$5-coins to \$2-coins to \$0.5-coins is

28 : 48 : 88

= 7 : 12 : 22

資料來源： I am HKCEE MATH A grade, I am HKCEE MATH A grade, I am HKCEE MATH A grade
• Mary has 28 \$5-coins, some \$2-coins and some \$0.5-coins. If the ratio of the value of \$5-coins to that of \$2-coins to that of \$0.5-coins is 35 : 24 : 11, find

(a) the number of \$ 2-coins Mary has,

let A be the number of \$2-coins

2 x A / (5 x 28 + 2 x A) = 24 / (24 + 35)

2A x 59 = 24 x (140 + 2A)

118A = 3360 + 48A

70A = 3360

A = 48

(b) the ratio of the number of \$5-coins to \$2-coins to \$0.5-coins

Let B be the number of \$0.5-coins

0.5 x B / (5 x 28 + 0.5 x B) = 11 / (11 + 35)

0.5B x 46 = 11 x (140 + 0.5B)

23B = 1540 + 5.5B

17.5B = 1540

B = 88

the ratio of the number of \$5-coins to \$2-coins to \$0.5-coins :

28 : 48 : 88

= 7 : 12 : 22

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