Using Graphs to Save Time

1. By use of Helen's chart (gas @ 20¢; oil @ $1.20; alcohol @ 90¢) find the cost of 6 gallons of gasoline; 8 gallons; 16 gallons; 3 gallons; 7 gallons; 24 gallons.

2 gallons of alcohol; 3 gallons; 5 gallons; gallon. 2 gallons of oil; 3 gallons; gallon; 24 gallons.

2. A man bought 8 gallons of gasoline, a gallon of alcohol, and 1 gallons of oil. What was his bill?

3. How much alcohol can be purchased for $5.40? for $3.60? for $9? for $1.35?

4. How much gasoline can be purchased for $1.80? for $3.20? for $5.60?

5. How much oil can be bought for $6? for $3? for $7.20?

Cost Formulas. Graphs

1. If eggs cost 30 cents a dozen, write a formula for the cost of eggs and draw a graph of this formula.

2. If tea is 45 cents a pound, write a formula for the cost of tea, and draw the graph of the formula.

3. Write formulas and draw graphs to represent the cost of potatoes at $1.80 a bushel; milk at 12¢ a quart; bananas at 30¢ a dozen.

4. Henry Jones, a plumber, received 90 cents an hour for his work. Make a formula to find the cost of hiring Henry. Draw a graph from your formula and from your graph find how much it would cost to hire him for 6 hours; for 7 hours; for 4 hours. Is this a function graph?

5. From your chart in example 4 find out how many hours Henry worked when he received $4.50; $3.15; $2.10.

6. Make a fuel cost chart, showing anthracite coal at $13.50 a ton, bituminous coal at $10 a ton, and coke at $11.50 a ton.

7. Mr. Estell burns in a season either 10 tons of anthracite, 11 tons of bituminous, or 13 tons of coke.

your graph what each

would cost.

8. Draw a graph to represent the meridians, the equator, and the parallels of latitude. Then find the point that represents 15° east and 23° south; 30° west and 40° north. Use the meridian of Greenwich as a starting point for your measurements east and west.

Graph of Parcel Post Rate. The parcel

Find from

COAL-MINING

post rates for the different zones of the United States Postal Service can be put in formulas for the different zones, and graphs can be made for each of the zones for the different numbers of pounds sent. For the first and second zones the first pound costs 7 cents and each additional pound costs 1 cent. This gives us the formula

C = 7+ P,

where C represents the cost of postage in cents and p, the number of pounds above the first pound.

That is, if we were to send 2 pounds, our formula becomes

C

=

7¢16. Or C = 8¢

since 2 pounds is 1 pound more than the first pound. For 6 pounds we would have

C = 7¢ + 5¢. Or C 12¢

=

since 6 pounds is 5 more than the first pound.

Saving Time with Parcel Post Graphs

1. Study the accompanying graph and from it find the cost of sending 3 pounds to any place in the first or second zone; 6 pounds; 9 pounds.

Cents Y

Zones 1 and 2

2. The formula for the third zone is C = 8+2 p. Construct a similar graph for this formula and from your graph, find the cost of sending 1 pound; 5 pounds; 10 pounds.

3. The formula for the fourth zone is C = 9+ 4 p. Construct a similar graph for the cost in this zone and then from your graph find the cost of sending 5 pounds; 10 pounds; 23 pounds.

=

10+ 6 p.

4. The formula for the fifth zone is C Construct a similar graph for the cost in this zone and find the cost of sending 4 pounds; 9 pounds.

=

5. The formula for the sixth zone is C 11+8 p. Construct a similar graph for finding costs in this zone and find the cost of sending 5 pounds; 10 pounds.

=

6. The formula for the seventh zone is C 13+ 10 p. Make a similar graph for this formula and find the cost of sending 12 pounds; 25 pounds.

=

7. The formula for the eighth zone is C 14+ 12 p. Construct a cost formula graph for this zone and find the cost of sending 15 pounds; 20 pounds.

Cumulative Review

(Use short-cuts for the several problems which permit.) 1. John spelled 192 words correctly out of 200. What per cent were right?

2. On a certain day in June the temperatures reported for each hour from midnight on were:

71° 69° 70° 69° 68° 67° 66° 68° 70° 72° 73° 74° 78° 83° 84° 85° 88° 87° 87° 86° 85° 84° 81° 80°

Find the average temperature for that day.

What was the lowest (or minimum) temperature that day? At what hour?

3. After spending one third of his money a boy had $24 left. How much had he at first? How much did he spend? 4. What number is as large as .05625?

5. You are going to take a motor trip. You know the distance in miles and the amount of time in hours that you plan to allow. How would you find your average speed in miles per hour?

6. What is the interest at 6% on $1200 for 60 days? for 30 days? for 15 days? for 90 days? for 4 months? Work this by formula.

7. Which of the following is the larger per cent of gain on the selling price: an article sold for $21.25 giving a gain of $4.25 or an article sold for $30 giving a gain of $6.60? How many per cent larger?

A POWDER EXPLOSION

10. Add: $75.16, $26.49, $56.84, $124.38, $207.47, and $372.16.

11. $800,000 had been contributed for an endowment fund to a certain college. If this was of the total amount sought, how much was the total? How much more must be subscribed to reach the total?

12. A tennis court is 78 feet long and 36 feet wide. What is its perimeter?

How much would it cost to cover the court with clay at 40 cents a square yard?

13. A farmer received $1.10 a bushel for his wheat, which yielded 18 bushels to the acre. If the following represents the cost of producing wheat, what is the farmer's gain on one acre?