Answer:
Step-by-step explanation:
Given that a large mixing tank initially holds 400 gallons of water in which 70 pounds of salt have been dissolved. Pure water is pumped into the tank at a rate of 4 gal/min, and when the solution is well stirred, it is then pumped out at the same rate.
Let Q(t) be the quantity of salt at time t.
Q(0) = 70 pounds
Inflow of water = outflow = 4 gal/min
So resulting volume of tank at time t = 400 gallons
Rate of change of salt = inflow - outflow
= 0 - 
i.e. 
This is a variable separable equation

Use when t =0 Q = 70
A =70
So A(t) = Q(t) =
and
A(0) = Q(0) = 70 lbs.
Answer:
x > 10
Step-by-step explanation:
Given
x - 3 > 7 ( add 3 to both sides )
x > 10
Answer: The answer is (C) 180°.
Step-by-step explanation: Given that m∠A = 40°. ∠B is a complement of ∠A and ∠C is a supplement of ∠B. We are to find m∠B + m∠C.
Since ∠B is a complement of ∠A, so we have

Now, since ∠C is a supplement of ∠B, so we have

Therefore,

Thus, (C) is the correct answer.
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