Hi all! I've been struggling with this problem :)
"A tank has 5000L of pure water. Brine containing 30g of salt/liter is pumped into the tank at a rate of 25L/minute.
1. Show the concentration of salt after t minutes in grams/liter is C(t)=(30t)/(200+t)
2. What happens to the concentration as t-infinity?"

Question

Hi all! I've been struggling with this problem :) 
"A tank has 5000L of pure water. Brine containing 30g of salt/liter is pumped into the tank at a rate of 25L/minute. 
1. Show the concentration of salt after t minutes in grams/liter is C(t)=(30t)/(200+t)
2. What happens to the concentration as t->infinity?"

anonymous · Answer

2. the solution will go to 30g salt/Liter as t->infinity

anonymous · Answer

cool that was my answer for 2 :)

anonymous · Answer

after 1 minute there will be 30 g of salt in 5025 litters

ganeshie8 · Answer

^^

so, after $t$ minutes there will be $30*t$ g of salt in $5000 + 25t$ liters

ganeshie8 · Answer

Oh wait a sec, 
but we're getting 25L of salty water into the tank, lets account that

ganeshie8 · Answer

it wud be :-

after $t$ minutes there will be $25*30*t$ g of salt in $5000+25t$ liters

anonymous · Answer

so its a matter of simplifying   750t / (5000 + 25t)  ?

anonymous · Answer

yes    C(t)  =      25 *30t
                      -----------    =       30t / (200 + t)
                        25( 200 + )

anonymous · Answer

*  correction 25 ( 200 + t)

anonymous · Answer

thats the denominator in middle term