a proofreader can read 200 pages one in 6 hours and one in 9 hours. Can both meet a 3-hour deadline to work to read the 200 pages?

Proofreader 1:

6 hours = 200 pages

1 hour = 200 : 6 = 33 1/3 pages

Proofreader 2:

9 hours = 200 pages

1 hour = 200 : 9 = 22 2/9 pages

Proofreader 1 + Proofreader 2:

1 hour = 33 1/3 + 22 2/9 = 55 5/9

3 hours = 55 5/9 x 3 = 166 2/3

They can read 166 2/3 in 3 hours.

Answer: No, they cannot meet the deadline to read 200 pages in 3 hours.