please help(as i said, it needs brains )
1. a worker suffers a 20 percent cut in wages. he regains his original pay buy obtaining a rise of?
(its not 20...!)
2. m men can do a job in d days, then the number of days in which m+r men would do the same?
3. a boy walks from his home to school at 6kmph . walks back at 2 kmph. avg. speed=?