rate of-work
DESCRIPTION
TRANSCRIPT
![Page 1: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/1.jpg)
by D. Fisher
![Page 2: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/2.jpg)
Copyright• Notice: All of the images used in this
presentation are from the internet and are publicly available. Many of them came from Wikipedia.
• The content of these presentations are provided by teachers and are presumed to be in the public domain.
• If any of these materials are used inappropriately, please inform the author, and they will be removed immediately or credit given.
![Page 3: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/3.jpg)
Marge can clean the house in 3 hrs. Lisa can clean it in 5 hrs.
How long will it take them to clean the house if they both work together?
![Page 4: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/4.jpg)
Marge can clean the house in 3 hrs.,
so she does 1/3 of the house per hour.
![Page 5: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/5.jpg)
Lisa can clean the house in 5 hrs.,
so she does 1/5 of the house per hour.
![Page 6: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/6.jpg)
Let T T be the time in hours.
13 TT + 1
5 TT = 1
![Page 7: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/7.jpg)
1/3T + 1/5T = 1
15(1/3T + 1/5T) = 15(1)
5T + 3T = 15
8T = 15
T = 15/8
17/8 hrs.
![Page 8: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/8.jpg)
Bart can wash the car in 20 min.Homer can wash it in 30 min.How long will it take them to wash the car if they both work together?
![Page 9: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/9.jpg)
Bart can wash the car in 20 min.,
so he does 1/20 of the car per min.
![Page 10: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/10.jpg)
Homer can wash the car in 30 min.,
so he does 1/30 of the car per min.
![Page 11: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/11.jpg)
Let M M be the time in minutes.
120 MM + 1
30 MM = 1
![Page 12: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/12.jpg)
1/20M + 1/30M = 1
60(1/20M + 1/30M) = 60(1)
3M + 2M = 60
5M = 60
M = 12 min.
![Page 13: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/13.jpg)
![Page 14: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/14.jpg)
Mr. Skinner can enroll 15 students per hr.
Mr. Chalmer can enroll 20 students per hr.
How long will it take them to enroll 140 students working together?
![Page 15: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/15.jpg)
Minutes work better than hours.
Mr. Skinner enrolls 15 students per 60 min.,
so he enrolls 15/60 or 1/4 students per min.
![Page 16: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/16.jpg)
Minutes work better than hours.
Mr. Chalmer enrolls 20 students per 60 min.,
so he enrolls 20/60 or 1/3 students per min.
![Page 17: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/17.jpg)
1/4M + 1/3M = 140
12(1/4M + 1/3M) = 12(140)
3M + 4M = 1680
7M = 1680M = 240 min.
= 4 hrs.
![Page 18: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/18.jpg)
![Page 19: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/19.jpg)
Mrs. Krabappel can grade a set of papers in 11/2 hrs.
Miss Hoover can grade them in 80 min.
How long will it take them to grade one set if they both work together?
![Page 20: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/20.jpg)
Minutes work better than hours.
Mrs. Krabappel grades 1/90 of a set per min.
![Page 21: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/21.jpg)
Miss Hoover grades 1/80 of a set per min.
![Page 22: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/22.jpg)
1/90M + 1/80M = 1
720(1/90M + 1/80M) = 720(1)
8M + 9M = 720
17M = 720
M = 426/17 min.
![Page 23: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/23.jpg)
Approximately how long would it take them to grade 3 sets if they both work together?
![Page 24: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/24.jpg)
1/90M + 1/80M = 3
720(1/90M + 1/80M) = 720(3)
8M + 9M = 2160
17M = 2160
M = 1271/17 min. A little more than 2 hrs.
![Page 25: Rate of-work](https://reader035.vdocument.in/reader035/viewer/2022081413/5481d9c7b4af9fcd398b4835/html5/thumbnails/25.jpg)