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71 qrs:
28 lb. in a qr.

LESSON 28.

8. yd. 6. If 17 cwt. 3 qrs. 17 lb, to- 15

330 bacco, cost £133 13s. 4d.

15)330(22 how much is that an ounce?

30 Answer, id. cwt. 17 3 qrs. 17 lb.

30
4

LESSON 30.
If 270 dollars a year, will

supply 12 persons in a family 585

with wheat at 187} cents ą

bushel, how many persons 142

will the said 270 dollars sup2005 lb.

ply with bread, when wheat 16 oz. in a pound.

is at 125 cents a bushel ?

Answer, 18 persons. 12030

cents. P. cents. 2005

187.5 : 12 :: 125

12 32080 ounces. £ 133 13 4

125)2250.0(18 persons. 20

125

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32080 d.
d.

LESSON 31.
32080
i 32080

If 100 cents make 4s. 6d. 32080)32080(1d. or 54 pence sterling, what 32080

sum will 100 dollars make LESSON 29. in sterling currency? A piece of cloth cost £16

Answer, £22 10s. 10s. the price of a yard was

cents. d. cents. 158.; how many yards were

100 54 :: 10000 there in the piece?

1100)5400100 Answer, 22 yds.

12)5400d. f 16 10

210) 4510s.

£ 22 10s. 20

Sterling is the currency of 330s.

Great Britain. If 158. will buy 1 yard,

Halifax and Canada cur. how many will 330s. buy? rency has 58. to the dollar. .

LESSON 32.

LESSON 33, If 4s. 6d. or 54 pence sterling make 100 cents, what If 100 cents make 60 pence sum will £ 45

9 sterling Halifax currency, how much make in cents ?

will 100 dollars make in HaliAns. 20200 cts. or 202 dol.||fax? Answer, £ 25. d. cents. d.

OPERATION.
54 : 100 :: 10908
54)1090800* (20200 cents. cents. d.

cents.
108
£ 45 9

100 : 60 :: 10000
20

x60 by 10000, then: by 108
,. 108
108

909 Thus, 1100)6000100
12

126000 d.
...00

210) 50|0s. 10908d.

£ 25 Note.—In England a dollar contains

4 6 In South Carolina and Georgia,

4 8 In Nova Scotia and the Canadas,

5 0 In New England,f Virginia, Kentucky, and Tennessee,

6 0 In New Jersey, Pennsylvania, Delaware, and Maryland,

76 In New-York and North Carolina,

8 0 Note. But for about thirty years past, North Carolina has estimated the dollar at ten shillings. LESSON 31.

LESSON 35, If 58. make 100 cents, how If 100 cents make 6s. or 720. many dollars will £ 52 158. New England currency, how make? Ans 211 dollars.! much will 100 dollars make

in New England currency? s. cents. £ 52 15

d. c. Ans. £ 30. 5: 100 :: 1055 20 5)105500

100:72:: 10000 || 12)7200d. 21100 1055 1100)720000 210) 600 7200d.

£30 * Two ciphers amnexed to multiply by 100.

+ New England is composed of the following states, viz. Vermont, New Hampshire, Commonwcalth of Massachusetts, Rhode Island and Connecticut,

8.

C.

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C.

LESSON 36.

LESSON 40. If 6s. make 100 cents, how

If 90 pence make 100 cts. many dollars will £ 216 185.|| how many dollars will £ 35 make ? Ans. 723 dolls.

12s. 6d. make? S.

Ans. 95 dollars. 6: 100 :: 4338 | £216 18s.

d. cts.

d. 6)433800 20

£. S. d.

90 : 100 :: 8550 35. 12 6 72300 4338s.

9/0)8550010 20 LESSON 37.

9500 cts. If 100 cents make 8s. New

712s. York currency, what sum

12 will 100 dollars make?

8550d.
Ans. £ 40.

LESSON 41.
C.
100 : 8: : 10000

If 100 cents make 4s. 8d. 1100)800100

in South Carolina and Geor210) 8010s.

gia, what sum will 100 dollars £ 40

make? Ans. £23 6s. 8d. LESSON 38.

4s. 8d. equal 56 pence. If 8s. make 100 cents, how cts. d. cts. many dollars are in £ 455 100 : 56 : : 10000 12s.? Ans. 1139 dols.

1100)5600100 S. cts.

12)5600d. 8: 100 :: 9112 455 12

210)4616s. 8d. 8)911200 20

£ 23 6s. 8d.
113900 cts.
9112s.

LESSON 42.
LESSON 39.

If 56d. make 100 cents,
If 100 cents make 7s. 6d. how many dollars will £ 21
Pennsylvania currency, what| 98. 4d. make?
sum will 100 dollars make ?

Ans. 92 dollars. Ans. £ 37. 108.

d. cts.

d. £. OPERATION.

56 : 100 :: 5152 21 94 7s. 6d.=90d.

20

56)515200(9200 cts. d. cts.

504 100 : 90 :: 10000

429s. 1100)9000100

112

12 12)9000d.

112

5152d, 210)7510

.. 00 £ 37 10s.

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S. d.

COMPOUND PROPORTION.

This is called the Double Rule of Three, or, Rule of Five. In this Rule five terms are given to find a sixth.

EXAMPLE If 4 men can reap 16 acres in 8 days, how many men can reap 48 acres in 4 days?

Answer, 24 men. The three first terms form a supposition, the fourth and fifth make a demand, and the sixth gives the answer.

As in simple Proportion, so in this; if more require more, or less require less, it is direct.

And, if more require less, or less require more, it is inverse.

“ If the proportion is direct, the sixth term must bear such proportion to the fourth and fifth, as the third term bears to the first and second.

But if the proportion is inverse, then the sixth term must bear such proportion to the fourth and fifth, as the first bears to the second and third, or as the second bears to the first and third.”

RULE FOR STATING. Take those terms which form the supposition in the above example, and begin thus :

1. Let the principal cause of action be placed in the first term; as,

4 men: 2. Let that which denotes time, distance, &c. be in the second term; as,

8 days 3. Place the remaining number of the suppesition in the third term; as,

:: 16 acres Then the work will stand thus :

men. d.

acres.

4:8: : 16 See Lesson C. Card 31.

4. Place the other two terms, which move the question, under those of the same name, thus:

men. d. acres.

4 : 8: : 16 See Lesson D. Card 31.

4:: 48

128

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KEY TO CARD No. 31. 5. If the blank fall under the third term, then multiply the first and second terms together for a divisor, and the other three for a dividend.

But, if the blank fall under the first or second term, then multiply the third and fourth terms together for a divisor, and the other three for a dividend, the quotient in either case will be the answer.

PROOF IS PERFORMED By two statings in simple proportion.

OPERATION OF THE AFOREGOING EXAMPLE. men d. acres. 4:8:: 16

16 third term. 4:: 48

4 fourth term.

64 a divisor.
48 fifth term.

64)1536(24 men.
8 second term.
384

256
4 first term.

256 1536 a dividend.

Now say if 8 days require

12 men:: how PROOF OF THE AFOREGOING

many men will 4 days require ? d.

d. We will suppose that the

8 : 12 :: 4 men reap during the time of

12 8 days; then say,

If 16 acres : require 4 men 4)96(24 mėn. :: how many men will 48 In this last statement, the acres require ?

third term is less than the acres. first and requires the fourth 4 :: 48

to be greater than the second, 4

and shows that less requires

more; therefore the propor16)192(12 men. tion is inverse. 16

LESSON 1.

If 56 bushels of corn will . 32 By this operation we find how many bushels will sup

supply 7 persons 4 months, that 48 acres require 12 men (ply 46 persons 10 months ? if they reap during days.

Answer, 920 bushels.

STATEMENT.

men.

acres.

men.

16 :

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