Please tell me how to solve below problem (C)

Suppose that a room containing 1400 cubic feet of air is originally free of carbon monoxide [CO]. Beginning at time t = U, cigarette smoke containing 6% CO is introduced into the room at a rate of 0.7 cubic feet per minute. The well-circulated smoke and air mixture is allowed to leave the room at the same rate. Let A(t) represent the amount of CO in the room {in cubic feet} after 15 minutes. (A) Write the DE model for the time rate of change of C0 in the room. Also state the initial condition. dA ,. 0.7 A(0) =i 0 l or (B) Solve the IVP to find the amount of CD in the room at any time t > 0. A\") = 8_,.1_ Brie\"DOOM J' do (C) Extended exposure to a CO concentration as low as 0.00012 is harmful to the human body. Find the time at which this concentration is reached. t 2 minutes