Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

14. If 4 yard of cloth cost $2, what will 3 ells F. cost?

2 x 3 15. If yard of cloth cost $2.25, what will 5 ells English cost ? What will 5 ells French cost ?

2.25 x

EXAMPLES.

1. If 12 bushels of wheat cost $15, what will 42 bushels cost?

Given 12 bushels and $15.
Required 42 bushels and ?

[ocr errors]

2. If 15 bushels of oats cost $4.50, what will 75 bushels cost?

Given 15 bushels and $4.50.
Required 175 bushels and ?

$4.50 X 1 3. If 12 bushels of wheat cost $15, how many bushels will $52} buy?

Given 12 bushels and $15.
Required ?

and $52.50.
521

2 1

= 12 x = 42 bushels. 15

12 x

3Q
&

4. If 15 bushels of oats cost $4.50, how many bushels will $22.50 buy?

Given 15 bushels and $4.50.
Required ?

and $22.50.

15 x

8 2 5

= 75 bushels.

5. If a man travel 48 miles in 6 hours, how many miles will he travel in 56 hours at the same rate ?

Ans. 448 miles. 6. If 20 bushels of wheat yield 4 barrels of flour, how many bushels will be required for 15 barrels of flour?

Ans. 75 barrels. 7. If 20 bushels of wheat yield 4 barrels of flour, how many barrels of flour will 75 bushels yield ?

8. If a man travel 50 miles in 2 days, how long will it take him to perform a journey of 375 miles at the same rate ?

9. If a staff 3 feet long cast a shadow 4 feet, what will be the length of the shadow of a steeple 180 ft. high ?

Given 3 ft., staff and 4 ft., shadow.
Required 180 ft., steeple and ? shadow.

Shadow of steeple 240 ft.

10. If the interest of $100 for one year is $6, what is the interest of $500 for the same time? Ans. $30.

11. If a man's salary amounts to $1500 in 3 years, how much will it amount to in 7 years ?

12. If 124 bushels of wheat cost $15, what will 353 bushels cost ? 351 X 2 = 71

15 x 11. 124 x 2 = 25 13. If f of a barrel of flour cost $6, what will 52 barrels cost? The 54 is a multiplier and the f is a divisor.

6 x 8 x 14.

14. If 51 bushels of wheat cost $6:60, what will 373 bushels cost ?

.20

6.69 x x 112

= $44.80. 15. If 4 of an acre of land is worth $36.40, what is the value of 15 1g acres at the same rate ?

15% = 413 $36.40 X X 278 16. If 74 acres of land cost $1560, what will of an acre cost?

Ans. $150. 17. The assets of a firm are $48576 and the liabilities $97648 ; how much will a creditor receive to whom is owing $1654?

[blocks in formation]

18. If is of a yard cost $zy, what will of a yard cost?

Ans. $2 19. If 7 of a ship cost £19, what is of it worth?

Ans. £32. 20. What will 57 acres 3 rods and 24 perches of land cost, if 5 acres 2 rods and 6 perches cast $224.64 ? Reduce to perches.

Ans. $2348.83+. 21. If $1.50 will buy 6 lbs. sugar, how much sugar will $36.50 buy?

22. If 54 yards of cloth cost $7.15, what will 727 yards cost?

$7.15 x 145 23. If 41 lbs. ham cost 87 cents, what will 354 lbs. cost?

Ans. $6.79+. 24. If .75 of a ton of hay cost $15, what will 2.25 tons cost?

Ans. $15. 25. If 160 acres of land cost $400, what will 830 acres cost ?

26. If I of a ship cost $4500, what will H cost ?

27. If .25 of an acre of land is worth $32, what is .875 of an acre worth ?

28. If 5 yards of muslin cost 46 cents, what will 201 yards cost ?

Ans. 162 cents. 29. If 3 yards of cloth cost $15.75, what will 6 ells English cost ?

Ans. $39.371. 30. If 5 ells Fl. cost $15.15, what will 6 ells Fr. cost ?

In the preceding examples, the ratios were all direct; as in those cases any increase in the required term of the ratio demanded a similar increase of the unknown; but there are cases which require the ratio to be inverted, such as, the more men employed, the less time will be required to perform a piece of work; the more hours employed in the day, the less days; the wider the material, the less yards it will take to make a garment, etc.

These cases of inverse ratio are readily detected by asking this question : “Will an increase of the required term of the ratio demand an increase in the unknown term ?" If it does, the ratio is direct; but if an increase in the required term of the ratio demand a diminution of the unknown term, the ratio must be inverted; thus,

PROBLEM.

If 4 men can do a piece of work in 10 days, how long will it take 8 men to do the same work?

[merged small][merged small][merged small][ocr errors]

COR.—It is evident that 8 men will do it in less time; that is, in one-half the time that it will take 4, which ratio is expressed by the diminishing ratio of 4 and 8,

at is, f = 1, in which the given term is the numerator of the ratio and the required term the denominator.

EXAMPLES,

1. If 5 men can dig a ditch in 20 days, how many men will dig it in 25 days?

Given 5 men and 20 days.
Required, ? and 25 days.

$ men x 8 = 4 men.

REM.-An increase in the 25 will require less men.

2. If 6 horses eat a certain quantity of hay in 30 weeks, how many horses will consume the same quantity of hay in 9 weeks?

Given
Required,

6 horses and 30 weeks.

? and 9 weeks.

10

6 horses x 30

= 20 horses.

3

3. If a man perform a journey in 12 days, when the days are 9 hours long, how many days of 12 hours will it take him?

Given
Required,

12 days and 9 hours.

? and 12 hours.

« ΠροηγούμενηΣυνέχεια »