Al is tied to a chair & placed in a closet into which poison gas is being pumped at a rate of .2t cubic feet per minute, where t is number of minutes since gas started pumping. The mixed air escapes at the same rate through the crack under the door. The gas becomes deadly when the air in the room contains .8 cubic feet of the poison gas. If the spy takes 3 minutes to get untied, how long will he have to get out beforethe gas reaches lethal concentration?

Question

pfenn1 · Answer

Your teacher has a weird sense of humor but my 17-year-old loves this problem. What we want to find out is how long it takes for the room to contain 0.8 cubic feet of poison gas. So the total amount of gas in the room at any time after the gas is turned on is  given by the equation:$$T=0.2t=0.8$$

pfenn1 · Answer

Solve for t.

anonymous · Answer

If t=4 then he has 4 minutes, thus only one minute to get out?

pfenn1 · Answer

Yes, great! You got it.

anonymous · Answer

One question, how do you know what the "lethal concentration" is?

pfenn1 · Answer

The lethal concentration is reached when "The gas becomes deadly when the air in the room contains .8 cubic feet of the poison gas." as was said in the problem.

anonymous · Answer

Oh okay! Thanks so much! :)

pfenn1 · Answer

You're welcome.