A 100-gallon tank is initially filled with pure water. Salt solution begins to flow into the tank from two sources. From one source, salt solution containing 1 pound of salt per gallon flows in at a rate of 2 gallons per minute. The second source gives 3 gallons of salt solution per minute at a decreasing concentration C(t) = 2e−2t pounds per gallon where t gives the number of minutes since the flow began. The well-mixed solution is pumped out at a rate of 5 gallons per minute. Find the mass of salt in the tank at time t.

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,

arc length = 6.63311 ft.

step-by-step explanation:

the formula the arc measure is:

arc length s=2πr(c)/360

where:

c   is the central angle of the arc in degrees

r   is the radius of the arc

π   is pi, approximately 3.142

using the above formula we get

s =

thus we find that arc length of an arc for a circle of radius 20 feet and central angle 19 degrees is

6.63311 feet