Answer:

Step-by-step explanation:
Volume of water in the tank = 1000 L
Let y(t) denote the amount of salt in the tank at any time t.
Initially, the tank contains 60 kg of salt, therefore:
y(0)=60 kg
<u />
<u>Rate In</u>
A solution of concentration 0.03 kg of salt per liter enters a tank at the rate 9 L/min.
=(concentration of salt in inflow)(input rate of solution)

<u>Rate Out</u>
The solution is mixed and drains from the tank at the same rate.
Concentration, 
=(concentration of salt in outflow)(output rate of solution)

Therefore, the differential equation for the amount of Salt in the Tank at any time t:

C is correct dont worry your correct
Answer:
2/15
Step-by-step explanation:
There is a 4/10 probability that she chooses blue the first time, but the second time it is a 3/9 chance because she didn't put the marble back so there are 9 marbles in total, 3 blue ones.
4/10 x 3/9 = 2/5 x 1/3 = 2/15
I hope this helps :)
Edit: Messed up the multiplication, whoops!
9514 1404 393
Answer:
34.58 in
Step-by-step explanation:
Relative to the angle marked in this right triangle, the side given is the "adjacent" side, and the side length wanted is that of the hypotenuse. The relevant trig relation is ...
Cos = Adjacent/Hypotenuse
Solving for the hypotenuse, we get ...
NP = (29 in)/cos(33°) ≈ 34.58 in