### Review Comments for Number 15

To see that the d.e. is 2-x(t)/(1+t), notice that 2gal/min*1lb/gal = 2lb/min is the input rate, while the output rate is 1gal/min*x(t) lb / (1+t) gal, since there is 1+t gal in the tank after t minutes (we start with 1 gal, and we increate 1 gal/minute (2-1).

Also notice that after t=9, the tank will overflow, since the tank holds 10 gal, and there is 1+t gal in the tank after t minutes (so at t=9, the tank will be full)

Great otherwise!

nice transition to the board for re-explanation of the problem, explained graphs very well
very good! great explanations!
wicked good, good plots, very interesting, presented it well
worksheet has good explanations, but the questions need to be in the worksheet in some form. Good presentation.
Nice, they know where they are going
Excellent work! That was a TOUGH problem and they explained it very well!
good understanding of problem; used Maple very efficiently; very good
good manipulation of Maple. I think I actually understand something!
You might explain in text how you got the d.e. You need to explain where t=9 came from in more depth. Very good explanation; good job!!
They seemed to do well with this given problem
Probably explore different values by inc. time and the value when it overflowed. Overall good job.
hard question to explain, good job
good, a little confusing, talked too long
long and complicated problem, but their explanation was thorough and easy to understand.
excellent presentation. well done and thought out. Handled questions very well. very long project. they did very well.
The explanations written on the board were very helpful, but these should have been put in text in the worksheet. Good explanation of defield. Good text comments on the rest. Good job and great effort on such a long problem.
How would salt concentration increase if initial amount is (for example) 2 pounds/gallon? Mixing the solution with incoming 1/1 solution would cause that to decrease towards the proportion of the incoming soluition?Woooo, lots of work. Good comments in problem.
good job!!!