90
-12. The newsstand had 90 copies at the beginning of the day
===
78
Answer:
I don't know search it up I picked B
okay it's 5 and I'm
If

is the amount of salt in the tank at time

, then the rate at which this amount changes over time is given by the ODE


We're told that the tank initially starts with no salt in the water, so

.
Multiply both sides by an integrating factor,

:




Since

, we have

so that the amount of salt in the tank over time is given by

After 10 minutes, the amount of salt in the tank is
Answer:
Each can of soda costs about 33 cents.
Step-by-step explanation:
This is just a simple division problem, and you can find the answer by dividing the cost of the sodas by the total number of sodas, so 4/12. If you complete that problem, the answer is 0.33 repeating, and since it asks you to round to the nearest hundredth, the answer is just 0.33. It is in dollar amounts, so the answer is 33 cents.