used during the month, if a keg holding 25 pounds cost $1.50. 47. The miner's other expenses for November were: file, 18; sharpening and repairing tools, 96; fuse, 15; 1 gal. lard oil @ 48. What were his total expenses? 48. Deducting expenses from the $60.72 received for his labor, what were the miner's net earnings for the month? 49. The cost of running a mine locomotive included $4.25 per day for labor, 50 for coal and oil, and 60 for repairs. Find the cost for 24 days. 50. The mine locomotive did the same work formerly done by 15 mules and their drivers. Find the cost of mule power for 24 days, if feeding, shoeing, and attending the mules cost $9 per day and drivers' wages amounted to $7.25 per day. 51. How much was saved by using the locomotive instead of the mules? 52. After the coal was mined it was sent to the breaker where the slate was picked out by breaker boys, and the coal sorted into sizes. If the 43 breaker boys were paid $219.30 in 6 days, how much did each receive per day? 53. Of the coal mined, was lost by blasting, breaking, and adhering to the slate. Find the loss in one day when 1365 long tons of merchantable coal were obtained. 54. The mine operator's expenses on 850 long tons of chestnut coal that he sold at $3.40 per ton were $2.08 per ton for mining and 96¢ per ton for handling. Find his profits on this sale. 55. It cost the retailer who bought this coal 85¢ per ton for freight, and 75 per ton for handling. If he sold the coal at $6.25 per short ton, how much did he gain? 56. One year, when there was a miners' strike, Pennsylvania produced 36,940,710 tons of anthracite coal, and the next year increased the output by 23,301,750 tons. How many tons were produced the year after the strike? 57. A new method of obtaining gold is by dredging on the surface. If one dredge picks up 85 cubic yards of earth weighing 1 tons each per hour, how many tons does it pick up in a day of 24 hours? 58. If each cubic yard of earth yields gold to the value of 17, what is the value of the gold dredged in one day? 59. If the amount of gold per cubic yard averages the same, find the value of gold dredged in 365 days. 60. Find the value of gold from 12 acres of gold-bearing earth, if it takes 11 days to dredge 1 acre. 61. Another method of mining gold is similar to that used in coal mining. How much did it cost to sink a gold mine shaft 102 feet, the expense being $16.75 per foot? 62. At certain levels horizontal passages called drifts were extended from the shaft. The various drifts had lengths of 184, 213, 239, 180, 93, 198, 41, and 156 feet, respectively. Find the total length of the drifts. 63. In making these drifts 1015 lb. of No. 1 powder at 16 of No. 2 at 12¢ per lb. were used. per lb. and 12,760 lb. 64. To ignite the powder 37,500 feet of fuse at 52 per 1000 feet and 98 boxes of caps at 60 per box were required. How much did the fuse and caps cost? 65. If 1520 pounds of candles were used at a cost of $114, how much did they cost per pound? 66. Find the cost of fuel, if 1671 cords of wood were used at $5 per cord and 5800 pounds of Cumberland coal at $15 per ton. 67. The other expenses were: labor, $9,750.75; tools, $216.46; timbers and ties, $85.86; steel rails, $283.86; water, $414.25; water pipe, $521.23; incidentals, $148.21. Find the entire expense of developing the drifts. 68. Find the cost per foot of the 1304 feet of drift. 69. The following men were employed in a gold mine: 2 foremen @ $4 per day; 2 brakemen @ $2.50 per day; 36 miners @ $2.75 per day; 2 smiths @ $4 per day; 2 smith's helpers @ $2 per day; 8 laborers @ $2.50 per day. Find their combined wages during a month of 26 working days. 70. Adding $249.15 for implements and $260.25 for materials used, what was the total expense for labor, implements, and materials? 71. If 1020 tons of ore were mined during the month, find the expense of mining per ton. 72. If it cost $2.48 in the mill to extract the gold from each ton of ore, find the cost of milling 1020 tons of ore. 73. What, then, was the expense of mining and milling each ton of ore? 1020 tons? 74. If of an ounce of gold was the average extraction per ton of ore, how many pounds of gold did the 1020 tons yield? 75. Find the value of the gold at $20.67 per ounce. 76. How much did this exceed the cost of mining and milling? 77. If the cost of power for this mine was $21 per horsepower by steam, or $7 per horsepower by electricity, find the saving on 1370 horsepower by using an electric motor instead of a steam engine. PERCENTAGE 322. The term per cent means per hundred, or hundredths. and the sign for it is %. 6 per cent, 6%, 186, and .06 represent the same thing, 6 hundredths. 323. The general name given to that part of arithmetic that treats of per cents is percentage. It is therefore merely an application of decimal fractions. WRITTEN EXERCISES 324. 1. Express decimally; then as a common fraction in its lowest terms: 5%; 100%; 125 %. 2. Express decimally; then as a common fraction in its lowest terms: 331 %; 1%. It is evident that % means of 1%. What does % mean? %? Express as a common fraction in its lowest terms: SUGGESTION. To how many hundredths is & equal? Express first as a decimal; then as per cent: 42. 2. What part of 24 is 6? What per cent of 24 is 6? .25 of 24? 25 % of 24? How many hundredths of 24 is 6? 3. Six is of what number? 6 is .25 of what number? 6 is 25 % of what number? In 1 you have found a per cent of a given number; in 2, what per cent one number is of another; in 3, a number when a per cent of it is given. These are the three chief types of problems in percentage. 326. The number of which some per cent is found is called the base. 327. The number of hundredths found is called the rate, or the rate per cent. 328. The result obtained by finding a per cent of the base is called the percentage. Thus, in 25% of 24 = 6, 24 is the base, 25% the rate, and 6 the percentage. 329. The sum of the base and the percentage is called the amount, and the base less the percentage is called the difference. THIRD PROG. AR. - 13 |