Answer:
C
Step-by-step explanation:
It’s blurry I can barely see it.
Since 13 can only be divided evenly by 1 and 13 (itself), it is called a prime number.
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)
Answer: yes
Step-by-step explanation: