A ball is thrown into the air from a height of 4 feet at time t=0. The function models this situation is h(t)=16t^2=63t+4 where t is measured in seconds and h is the height in feet. When will the ball reach a height of 50 ft

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?