Answer:
a) 
b) 
Step-by-step explanation:
By definition, we have that the change rate of salt in the tank is
, where
is the rate of salt entering and
is the rate of salt going outside.
Then we have,
, and

So we obtain.
, then
, and using the integrating factor
, therefore
, we get
, after integrating both sides
, therefore
, to find
we know that the tank initially contains a salt concentration of 10 g/L, that means the initial conditions
, so 

Finally we can write an expression for the amount of salt in the tank at any time t, it is 
b) The tank will overflow due Rin>Rout, at a rate of
, due we have 500 L to overflow
, so we can evualuate the expression of a)
, is the salt concentration when the tank overflows
60% of 20 is (0.6 x 20) = 12 passes
There are a further 30 quizzes remaining (50 total during the year minus 20 already written)
80% of 30 is (0.8 x 30) = 24 passes
The student has passed (12 + 24) = 36 quizzes out of 50 total, giving an overall pass percentage of ((36 / 50) x 100)) = 72%.
Answer:
10
Step-by-step explanation:
Solving:
1) Pass: Make the rule three (Directly proportional)
Two inch nails ______ grams (<span>Weight)
</span>15 ----------------------------35
n ----------------------------- 175
2) Pass: <span>Multiply cross
</span>

3) Pass: Simplify




Answer:
75 nails weigh 175 grams
D. is the answer
y - y1 = m(x - x1)
the slope is 2/3, so choose which point to be (x1, y1)