If 6 typists typing 8 hours a day (at equal speed) take 20 days to complete a manuscript. If the work is to be completed in 12 days, how many more typists should be employed if each typist works for 5 hours a day?​

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?