2. Concurrent Work Problems

3. t = time together a = first individuals time b = second individuals time 1 = the entire job

4. If Shelly can mow the yard in 3 hours and Kenny’s brother can mow the yard in 2 hours, how long will it take if they mow the lawn together ?

5. Wendy can build a clubhouse in 3 hours and Bebe can build a clubhouse in 4 hours, how long will it take if they build one clubhouse together?

6. 18.A sink can be filled in 3 minutes by the cold water faucet and in 5 minutes by the hot water faucet. How long would it take for the hot and cold water faucet to fill the sink together? Minutes

7. Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together?

8. Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together? Let x = the time working together

9. Work Problems about Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together? Let x = the time working together Stan can do 1/45 of the work in 1 minute Bobbie can do 1/30 of the work in 1 minute

10. Work Problems about Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together? Let x = the time working together Stan can do 1/45 of the work in 1 minute Bobbie can do 1/30 of the work in 1 minute

11. Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together? Let x = the time working together Stan can do 1/45 of the work in 1 minute Bobbie can do 1/30 of the work in 1 minute

12. Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together? Let x = the time working together Stan can do 1/45 of the work in 1 minute Bobbie can do 1/30 of the work in 1 minute

13. Work Stan needs 45 minutes to do the dishes, while Bobbie can do them in 30 minutes. How long will it take them if they work together? Let x = the time working together Stan can do 1/45 of the work in 1 minute Bobbie can do 1/30 of the work in 1 minute

14. Work A water tank can be filled in 12 hr by pipe A alone and in 9 hr by pipe B alone. How long would it take to fill the tank if both pipes were working?

15. Water Tank A water tank can be filled in 12 hr by pipe A alone and in 9 hr by pipe B alone. How long would it take to fill the tank if both pipes were working? A – 1/12 of the job in 1 hour B – 1/9 of the job in 1 hour h hours working together for the job 1/12 + 1/9 = 1/h

16. Shoveling Snow After a heavy snowfall, Butters can shovel all of the driveway in 30 minutes. If Pip helps, the job takes only 20 minutes. How long would it take Pip to do the job by himself?

17. Shoveling Snow After a heavy snowfall, Butters can shovel all of the driveway in 30 minutes. If Pip helps, the job takes only 20 minutes. How long would it take Pip to do the job by himself?

19. Conclusions Pip’s rate was 60. If Pip shoveled the drive way by himself it would take 60 minutes or 1 Hour.

21. 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?

22. Marge can clean the house in 3 hrs., so she does 1 / 3 of the house per hour.

23. Lisa can clean the house in 5 hrs., so she does 1 / 5 of the house per hour.

24. T Let T be the time in hours. 1 3 T+ 1 5 T= 1

25. 1 / 3 T + 1 / 5 T = 1 15( 1 / 3 T + 1 / 5 T) = 15(1) 5T + 3T = 15 8T = 15 T = 15 / 8 1 7 / 8 hrs.

26. 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?

27. Bart can wash the car in 20 min., so he does 1 / 20 of the car per min.

28. Homer can wash the car in 30 min., so he does 1 / 30 of the car per min.

29. M Let M be the time in minutes. 1 20 M+ 1 30 M= 1

30. 1 / 20 M + 1 / 30 M = 1 60( 1 / 20 M + 1 / 30 M) = 60(1) 3M + 2M = 60 5M = 60 M = 12 min.

32. 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?

33. Minutes work better than hours. Mr. Skinner enrolls 15 students per 60 min., so he enrolls 15 / 60 or 1 / 4 students per min.

34. Minutes work better than hours. Mr. Chalmer enrolls 20 students per 60 min., so he enrolls 20 / 60 or 1 / 3 students per min.

35. 1 / 4 M + 1 / 3 M = 140 12( 1 / 4 M + 1 / 3 M) = 12(140) 3M + 4M = 1680 7M = 1680 M = 240 min. = 2 hrs.

37. Mrs. Oduwale can grade a set of benchmarks in 1 1 / 2 hrs. Mrs. klarin can grade them in 80 min. How long will it take them to grade one set if they both work together?

38. Minutes work better than hours. Mrs. Oduwale grades 1 / 90 of a set per min.

39. Miss Klarin grades 1 / 80 of a set per min.

40. 1 / 90 M + 1 / 80 M = 1 720( 1 / 90 M + 1 / 80 M) = 720(1) 8M + 9M = 720 17M = 720 M = 42 6 / 17 min.

41. Approximately how long would it take them to grade 3 sets if they both work together?

42. 1 / 90 M + 1 / 80 M = 3 720( 1 / 90 M + 1 / 80 M) = 720(3) 8M + 9M = 2160 17M = 2160 M = 127 1 / 17 min. A little more than 2 hrs.

44. Work & Motion Word Problems