Answer:
C) One solution: 
Step-by-step explanation:
Hope this helps!
Answer:
9 years ( approximately)
Step-by-step explanation:
900(1.03)^t = 1200
(1.03)^t= 1.33
( 1.03)^t= ( 1.03)^9
So, t= 9
Answer:
a) 
b)
Step-by-step explanation:
Data
Brine a (Ba)

Brine b (Bb)

we have that per every minute the amount of solution that enters the tank is the same as the one that leaves the tank (15 Lt / min)
, then the amount of salt (y) left in the tank after (t) minutes: 
Finally:
a) 
b) 
being y(t) the amount of salt (y) per unit of time (t)