"If 9 examiners can examine a certain number of  answer books in 12 days, working
Channel: Doubtnut
Date: 2020-04-12

"If 9 examiners can examine a certain number of
  answer books in 12 days, working 5 hours a day for hw may hours a day would 4
  examiners a day for how many hours a day would 4 examines have to work in
  order to examine twice the number of answer books in 30 days?
`6`
b. `8`
c. `9`
d. 10"