Haji rows his canoe 10 mph in still water. he noticed one day that he could row 4 miles upstream in the same amount of time he could row 6 miles downstream. what was the approximate speed of the current that 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?