9. Water leaks from a tank at a rate /(t) = 4.2+0.197 gallons per hour where t is the number of hours since 7 AM. (a) Evaluate the integral: (4.2 + 0.197t) dt. (b) What is the meaning of this integral? In your answer use the numbers 1, 3, and your result from part (a) along with the units for each