156 FARM ARITHMETIC. 



530. A 1,600-pound horse walks two miles an hour for 

 10 hours. What pull may be expected ? 



531. A 1,500-pound horse is exerting a pull of 200 

 pounds while working 10 hours a. day. How fast should 

 he walk? How fast if pull is 150 pounds? If 100 

 pounds ? 



532. Two horses, one weighing 1,600 pounds and the 

 other 1,000 pounds, are walking at a rate of three miles 

 an hour. What pull are they exerting, provided that they 

 are doing a full day's work (10 hours) and that the 

 doubletree is properly adjusted? 



533. At what rate should these horses walk if the pull 

 is increased to a total of 520 pounds ? 



Effect of Duration of Work on Pulling Power. 



The standard day's work is 10 hours. If, however, 

 the working hours be decreased more may be required of 

 the horse either in speed, or load, or both. Experiments 

 indicate that between five and 10 hours, speed remaining 

 the same, the pull may be increased in the same ratio 

 as the hours are decreased. This may be shown as fol- 

 lows: 



Standard hours a day X standard pull = changed hours 

 a day X changed pull. 



534. A 1,200-pound horse walking 2.5 miles an hour 

 works for five hours. How many pounds pull may be 

 expected of him ? 



Process : 



10 X 120 = 5 X pull to be determined. 

 1,200 -f- 5 = 240, pounds pulling power. 



535. If this horse exerts a pull of 180 pounds, how 

 many hours should he work ? 200 pounds ? 120 pounds ? 



