RATIO AND PROPORTION  2

PROBLEMS

Do the problem yourself first!

11.  a)   In this proportion --

10 : 30 = 2 : 6.

1.  a)    -- which are the corresponding terms?  10 and 2; 30 and 6.

1.    b)  State the alternate proportion.

"10 is to 2 as 30 is to 6?"

 a) 2 : 8 = 6 : 24.

"2 is to 8 as 6 is to 24.  Alternately, 2 is to 6 as 8 is to 24."

 b) 12 : 4 = 36 : 12.

"12 is to 4 as 36 is to 12.  Alternately, 12 is to 36 as 4 is to 12."

 c) 2 : 3 = 10 : 15.

"2 is to 3 as 10 is to 15.  Alternately, 2 is to 10 as 3 is to 15."

13.  Common divisor.  Complete each proportion.

 a) 6 : 8 = 3 : 4. b) 12 : 18 = 2 : 3. c) 16 : 40 = 2 : 5.
 d) 12 : 200 = 6 : 100. e) 45 : 500 = 9 : 100.
 f) 350 : 1000 = 35 : 100.
 g) 24 : 75 = 8 : 25. h) 35 : 40 = 7 : 8. i) 21 : 63 = 3 : 9.

14.  Same multiple

4.    a)  If two numbers are multiplied or divided by the same number,
4.    a)  then the products will have the same ratio.

4.    b)  Write five pairs of numbers such that the first is three eighths
4.    b) of the second.

The elementary pair are 3 and 8. Now take the same multiple of each one. For example:  6 and 16,  9 and 24,  12 and 32,  15 and 40.

15.  Complete each proportion.

 a) 4 : 9 = 8 : 18. b) 4 : 9 = 12 : 27. c) 4 : 9 = 16 : 36.
 d) 7 : 8 = 21 : 24. e) 9 : 5 = 63 : 35. f) 3 : 8 = 15 : 40.
 g) 2 : 9 = 16 : 72. h) 6 : 5 = 54 : 45. i) 8 : 3 = 56 : 21.
 j) 7 : 8 = 42 : 48. k) 3 : 4 = 15 : 20. l) 11 : 2 = 99 : 18.
 16 5 : 20 = 8 : 32.

17.  In a class, the ratio of boys to girls was 4 to 5.  There were 20 boys.
17.  How many girls were there?  25

18.  In a survey, the ratio of Yes's to No's was 2 to 3.  There were 300
18.  Yes's.  How many No's were there?  450

19.  The ratio of white roses to red was 3 to 4.  There were 32 red roses.
19.  How many white roses were there?  24

10.  The ratio of white roses to red was 3 to 4.  Out of 28 roses, how
10  .many were white?

12.  For, 3 out of every 7 roses -- 3 white + 4 red -- were white. 3 is to 7, then, as what number is to 28? Since 28 is four times 7, the missing number is four times 3. There were 12 white roses.

11.  In a survey, the ratio of Yes's to No's was 2 to 3.  Out of 100
11.  responses, how many were Yes and how many No?

40 Yes and 60 No.  For, the Yes's were 2 out of 5, and the No's, 3 out of 5.  And 2 is to 5 as 40 is to 100; that is, as 20 × 2 is to 20 × 5.  3 is to 5 as 20 × 3 is to 20 × 5.

Continue on to the next section.

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