Introduction to mathematics by unknow

Author:unknow
Language: eng
Format: epub
Tags: Mathematics
Publisher: Boston ; New York : D.C. Heath
Published: 1916-03-25T05:00:00+00:00

15 ft. by 10 ft. were occupied by one person, how often would the air have to be completely changed to obtain pure air ?

2. How often would the air in a room 12 ft. by 11 ft. by Sift, have to be completely changed to obtain pure air for two persons ?

3. If there were 500 people in a lecture hall, how often would the air have to be completely changed to insure good ventilation ? Nine square feet of floor space is allowed to each person, and the hall is 11 feet high.

4. For good ventilation the air in a room containing one person needs to be changed every 45 minutes. What is the approximate size of the room ?

5. It has been found by experiment that the air in a room cannot be changed more than three times per hour without danger of drafts. What are the dimensions of a room that is just large enough to meet this ventilating requirement, when one person occupies the room ?

6. It has been found by experiment that one gas jet, when burning, uses as much air as two persons. By changing the air in a room occupied by one person once an hour during the daytime, good ventilation is secured. How many times per hour does it need to be changed in the evening when one gas jet is burning ?

7. When two persons occupy a room, good ventilation is secured in daytime by changing the air once each half hour. How often should the air be changed when 3 gas jets are lighted ?

8. The air in a room occupied by one person needs to be changed once every hour in the daytime and three times every hour during the evening. How many gas jets are burning ?

9. A kerosene lamp requires as much air as 4 persons. When 2 persons occupy a room, the air needs to be changed once every 2 hours. When a lamp burns in the room, how often does the air need to be changed ?

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