Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

Review Problems. 1. A farmer received 60 cents a bushel for 4 loads of corn weighing as follows: 2,564, 2,713, 3,000, and 3,109 pounds: how much did he receive for all ?

2. From a pile of wood containing 960 cubic feet was sold at one time 37 cords, at another time 2 cords: what was the remainder worth at $41 a cord ?

3. What will it cost to plaster the walls and ceiling of a room 18 by 20, and 12 feet high, at 40 cents per square yard?

4. Which will take the greater number of rods of fence, a 10-acre field in the shape of a square, or a field 80 rods long and 20 rods wide? How many rods ?

5. A man bought 33 acres of land at $225 an acre; he laid it out in lots 4 by 10 rods, and sold them at $100 apiece: how much did he gain by the transaction ?

6. The greatest depth of the telegraph cable from Newfoundland to Ireland is 2,500 fathoms: how many miles deep is it?

7. What part of a bushel is of a quart?

8. 103 quinine is made up into capsules of 2 grains each: what will it bring at 15 cents a dozen ?

9. Find the cost of a load of hay weighing 1 T. 683 lb. at $9.50 a T.

10. If in a watch-chain there is 1 oz. 10 pwt. 10 gr. of gold, how many such can be made from 15 oz. 4 pwt. 4 gr. of gold?

11. How many loads of coal, each weighing 1 T. 750 lb., are there in a car containing 20 T. 12 cwt. and 50 lb. ?

12. A square cistern, whose bottom is 6 feet, is 8 feet deep: how many barrels will it hold ?

13. A bin 8 feet long, 6 feet wide, and 4 feet deep, will hold how many bushels ?

14. I wish to build a bin large enough to hold 200 bushels of wheat: what should be the dimensions of the bin ?

Percentage.

ART. 251.—Per centum or per cent. means by the hundred. One per cent. means one hundredth, expressed also ido or .01 ; five per cent., or five hundredths, is expressed To or .05; ten per cent. is expressed 1% or .10 or .1. Per cent. is usually written %.

=

15 %

Per cent. is expressed in several ways, thus :

5 per cent., or 5 % Too .05. 4 per cent., or 4 % = To = .04. 15 per cent., or

.15. 124 per cent., or 121% =

.125. 64 per cent., or 61%

400

.0625. per cent., or

zo .005. 4 per cent., or 4% Ado .0025. 125 per cent., or 125 %

= 1.25.

15 100 25 200 2 5

=

=

[ocr errors]
[ocr errors]

=

125
100

ART. 252.-Every number is or for or 18 or ** or 18% of itself, since each of these fractions is equal in value to 1. It follows, therefore, that when we speak of 100 per cent. of any amount, we mean the whole amount.

ORAL EXERCISES.

1. Tell what part of any number is meant by 50% of it; by 25% ; by 75%; by 20%; by 40%; by 60%; by 80% ; by 90% ; 125%; 150%; 175% ; 200%.

2. What per cent. of a number is too of it? Téo ? 100 ? ? ? 300 ? 10 ? 10%? ? 3. What is 5% of 100? 200 ? 500 ? 1000 ? 4. What is 10% of 50 ? 80 ? 90 ? 190 ? 5. What is 25% of 200 ? 300 ? 400 ? 600 ?

6. What is 50% of 300? 180 ? 250 ? 300 ? 7. What is 100% of 500 ? 400 ? 100 ? 750 ?

8. Express decimally 1%; 5%; 6%; 8%; 10%; 121%; 20% ; 25%; 331%; 50%; 621%; 75%; 80% ; 100%; 125% ; 150% ; 200%.

DEFINITIONS.

ART. 253.-Percentage is the result obtained by taking a certain per cent. of the base.

ART. 254.—The Base is the number on which the percentage is computed.

ART. 255.—The Rate per cent. is the number of hundredths of the base to be taken,

ART. 256.—The Amount is the sum of the base and percentage.

ART. 257.–The Difference is the remainder after subtracting the percentage from the base.

Thus, if we take 12% of $500, the result is $60. The percentage is $60; the base $500; the rate .12; the amount $560, and the difference $440.

ART. 258.—The percentage, base and rate bear such relations to each other that if two of them are given, the third can be found.

ART. 259.—To find the percentage, the base and

rate being given.

ORAL EXERCISES.

1. What is 5% of $100 ?

Solution.—5% of any number is too of that number ; tdo of $100 is $1, and tốo is 5 times $1, which is $5.

What is

2.8% of 100 bushels ? 7. 30% of 180 miles ?
3. 10% of 150 gallons ? 8. 50% of $75 ?
4. 12% of 200 men ? 9. 60% of 320 feet?
5. 121% of 120 horses? 10. 90% of 500 yards ?
6. 25% of 120 acres ? 11. 100% of 1 cent ?

12. I bought 12 bushels of chestnuts and sold 25% of them : how many bushels did I sell ?

13. Harmon receives a monthly salary of $40, and saves 40% : how many dollars does he save each month ?

14. Susan had 45 pins, and gave Ellen 60% of them : how many pins did Ellen receive ?

15. In a certain election the successful candidate received 600 votes, and his opponent 90% as many : how many votes did the latter receive ?

16. Thomas bought a horse for $240, and sold it at & gain of 30% : what did he receive ?

17. Walter bought a cow for $90, and sold it at a loss of 20% : how much did he receive ?

18. James paid $12.50 for a railroad ticket, and his son paid 50% as much : how much did his son's ticket cost ?

19. A certain school has 120 pupils, of whom 40% are boys : how many are girls ?

20. A freight train ran 20 miles an hour. If thc speed of a passenger train was 150% of that, how many miles an hour did it run ?

21, John rode 40 miles on his bicycle on Monday; 20% farther on Tuesday, and 25% farther on Wednesday than on Tuesday: how many miles did he ride on Wednesday ?

WRITTEN EXERCISES.

1. What is 15% of $275 ?

Process.

$275

.15

Analysis.-15% of any number is .15 of it, and .15 of $275 is $41.25.

1375 275

$41.25

ART. 260.–Rule for finding the percentage, the base and rate being given.-Multiply the base by the rate per cent. expressed decimally.

Formula.—Percentage = base x rate per cent.

What is
2. 3% of $268 ?

6. 11% of 75.5 pounds ? 3. 4% of $365.50 ?

7. 15% of 149 bushels ? 4. 41% of 32 feet? 8. 1% of $60 ? 5. 6% of 250 bbl. ? 9. 1% of 200 miles ? 10. What is the difference between 15% and 371% of 160 bushels ?

11. A tract of land bought for $225 increased 125% in value : what was its value after the increase ?

12. The weekly edition of a newspaper is 28,500 copies, and the daily edition is 70% of the weekly edition : what is the daily edition ?

13. From a bill of goods amounting to $1,238.50, a deduction of 12% was made for cash : how much cash was

paid ?

Solution.—100% – 12%

88% ; $1238.50 x .88 = $1089.88.

14. Franklin having 600 bushels of grain, sold 127% of it to one man, and 371% of it to another: how many bushels did he keep ?

« ΠροηγούμενηΣυνέχεια »