A person named Rafiq’s annual income has increased for Tk. 3500 but there is no charge in the income tax payable for him since the rate of income tax has been reduced from 7% to 4%. Find his present income.

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi, r^3 , where r is the sphere’s radius.