A large tank is partially filled with 100 gallons of fluid in which 40 pounds of salt is dissolved. Brine containing 1 2 pound of salt per gallon is pumped into the tank at a rate of 6 gal/min. The well-mixed solution is then pumped out at a slower rate of 4 gal/min. Find the number of pounds of salt in the tank after 30 minutes. (Round your answer to two decimal places.

76.09 pounds

Step-by-step explanation:

From the information given:

At a slower of 4 gal/min, the solution gets pumped out;

So,

The differential of the equation is:

For the linear differential equation, the integrating factor is determined as:

Multiplying with the above integration factor;

By using the given condition:

A(0) = 40

40 = 50 + c (50)⁻²

10 = c(50)⁻²

OR

c = -10 × 2500

c = -25000

A = (50 + t) - 25000(50 + t)⁻²

The number of pounds of salt in the tank after 30 min is:

A(30) = (50+30) - 25000(50 + 30)⁻²

Thus, the number of pounds of salt in the tank after 30 min is 76.09 pounds.

22 dimes and 9 nickels

step-by-step explanation:

step-by-step explanation:

no, her answer is not correct.   we square the lengths of all sides and then determine whether the pythagorean theorem holds here:

9² + 15² = 306.   this is not equal to the square of the longest side ( that square being 395.   answer c is correct.