(15) Mr. Green's two boys hired a war garden and raised the following vegetables: 2 bu. potatoes; 11⁄2 bu. beans; 40 squash; 2 pk. of peas; 12 doz. corn; and 50 heads of lettuce. Their expenses were $8.75. How much money did they save by their industry, at the present day price quotations on these vegetables?

(16) A cooking class used the following materials during their lesson:

12 quarts of strawberries @ 25¢.

6 pounds of sugar @ 9; 1 dozen quart jars @ 121

1 dozen jar rubbers @ 1¢.

They sold the preserve for 85¢ per quart. What was the total profit?

(17) Mrs. Green uses 2 tons of coal for her kitchen range during July and August: Mrs. Smith, her neighbor, uses a gas range, burning 5,625 cu. ft. of gas, during the same period. The gas costs $1.25 for 1000 cu. ft.

a. What is Mrs. Smith's gas bill for July and August?

b. What is Mrs. Green's coal bill for July and August at the present price quotations?

c. Assuming that the same amount of heat is required in each case which is the cheaper fuel?

(1) How much did the wholesale cost of flour advance in

ten years? What per cent did it advance?

(2) How much did the retail cost advance in ten years? What per cent did it advance?

(3) The retail price in 1908 was what per cent higher than the wholesale price? (This is called "The Margin of Profit.")

(4) The retail price in 1918 was what per cent above the wholesale price? Was the margin of profit any greater in 1918 than in 1908?

(5) Give all the reasons you can for this advance in the prices of the above commodities.

(6) Answer the questions, 1, 2, 3, 4, for butter, sugar, steak, potatoes, and eggs.

(7) A child should consume one quart of milk daily; an adult should consume 1 pint daily. What would be the cost of the weekly supply of milk for a family of 5 children and two adults at present prices? The monthly bill?

CHAPTER XX

INTEREST

1. How will the study of ways of saving money or investing money be of service to you? How will this knowledge make you more valuable to your employer? Why should everyone have a bank account? Which is better,-to watch your money go, or to watch it grow?

2. If I hire an automobile for 4 hours at $3 an hour, how much do I pay for the use of it?

3. If I pay $24 a month for rent, what do I pay for the use of the house for 1 year?

4. If the house is worth $3600, what per cent of its value do I pay for the use of it?

5. If I borrow $3600, what do I have to pay for the use of it? Why? People who wish to use buildings, land, horses, etc., which belong to others, hire them and pay for their use. In the same way, people who need money hire it, and pay a certain per cent for the use of it. Money paid for the use of money is called interest, and is reckoned as a certain per cent of the amount borrowed, or principal. When a person says he will lend you a dollar at 6% per year, he means that you must pay him $.06 (6% of $1) for the use of it for one year. If the rate is 5% your interest is $.05, etc.

116. Interest. A commercial year has 360 days; what part of 1 year is 60 days? 6 days? What is the interest on $1 for 1 year at 6%? For 60 days? For 6 days? Since the interest for 1 year or 360 days equals $.06, and the interest of 60 days or of a year equals $.01, and the interest of 6 days equals .001, it is clear that .001 of any principal is equal to the interest for 6 days at 6%. What is the interest on $1 at 6% for 1 day?

(1) How do you find .01 of a number? .001 of a number? State a short way of finding the interest on any principal for 60 days at 6%; for 6 days.

ORAL EXAMPLES

(1) Find the interest on each of the following for 6 days at

(2) Find the interest on each of the above amounts for

12 days at 6%; for 18 days; for 24 days; for 30 days. (3) Find the interest on each of the following for 1 day at

d. $360

h. $720

1. $570

p. $510 (4) Find the interest on each of the above amounts, for 3 days at 6%; for 9 days; for 2 days.

ILLUSTRATIVE EXAMPLE (1): Find the interest on $624 for 48 days at 6%.

Solution: Finding .001 of $624 by pointing off three places to the left, gives $0.624, the interest for 6 days. 48×$0.624 = $29.952 or 6 times the interest for 48 days. Dividing this result by 6, gives $4.992, the required interest. This work may be shortened by cancellation:

ILLUSTRATIVE EXAMPLE (2): Find the interest on $225 for 1 year, 4 mo., 12 days at 7%.

Solution: 1 yr., 4 mo., 12 da. =492 days.

(5) At 6% find the interest on each of the following problems (reduce the time to days):

(1) $350 from May 1, 1914, to Sept. 10, 1914, (find the exact number of days) at 3%; at 2%; at 1%.

(2) A merchant borrowed $650 from Jan. 1, 1921, to July 23, 1921, at 9%. How much does he pay for its use? What would he have had to pay at 4%? At 8%?

(3) A manufacturer borrowed $2700 from Oct. 15, 1919, to Jan. 1, 1921, at 6%; what did he have to pay for the use of the money? Find what he would have to pay at each of the following rates:

1%, 2%, 3%, 4%, 5%, 7%, 8%, 9%, 10%, 12%

(4) If you loaned $500 at 6% on July 1, 1920, and it was paid back on Dec. 1, 1920, how much interest would it earn for you? What amount of money would you receive?

(5) A student borrowed $250 on Sept. 4, 1919, in order to complete his education. The rate of interest was 5%. What amount of interest was due Sept. 1, 1920?

(6) If your father has $6000 and spends $500 a year, how many years will the money last him? If he puts the $6000 in a bank, which pays a 5% interest, and draws out for expenses $500 at the end of each year, how long will the money last him?

(7) A dry goods dealer borrowed $4725 on the 1st of May. On the 1st of December following, he paid the amount which was $4890.375. What rate of interest did he pay?

(8) A man deposited $800 in a bank paying 6% interest; he kept it there until it was doubled. How long did he keep it there?