You are filling a right cylinder tank with colored sand. how much sand in cubic inches must you add to the tank with a radius of 20 inches and height of 5 inches, in order to fill the tank 4 /7 full?

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?