Please answer number 1 and 2 . Show complete solutions.

Solve the following problems: 1. Brine containing 3 lb/gal of salt enters a large tank at the rate of 4 gal/min and the solution well stirred leaves at 2 gal/min The tank initially contains 20 gal of water. What is the amount of salt in the tank after 7 min ? When will there be 150 lb of salt in the tank ? 2. A ball is dropped from a viscous fluid from rest with a resisting force numerically equal to 0.01v where v is the velocity in m/s. The mass of the ball is 3 kg. find the velocity of the ball at any time t