Aradio signal travels at 3.00 * 10^8 per second. how many seconds will it take for a radio signal to travel from a satellite to the surface of earth if the satellite is orbiting at a hieght of 3.54 * 10^7

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?