Answer:
Step-by-step explanation:
This is a differential equation problem most easily solved with an exponential decay equation of the form
. We know that the initial amount of salt in the tank is 28 pounds, so
C = 28. Now we just need to find k.
The concentration of salt changes as the pure water flows in and the salt water flows out. So the change in concentration, where y is the concentration of salt in the tank, is
. Thus, the change in the concentration of salt is found in
inflow of salt - outflow of salt
Pure water, what is flowing into the tank, has no salt in it at all; and since we don't know how much salt is leaving (our unknown, basically), the outflow at 3 gal/min is 3 times the amount of salt leaving out of the 400 gallons of salt water at time t:

Therefore,
or just
and in terms of time,

Thus, our equation is
and filling in 16 for the number of minutes in t:
y = 24.834 pounds of salt
8x - amount of boys
7x- amount of girls
8x + 7x = 195
15x= 195 ( divide by 15)
x= 13
8x = 8 x 13 = 104
7x = 7 x 13= 91
there are 104 boys, and 91 girls.
Answer: (2,3)
Hope this helps! good luck! Have a wonderful day! :)
Answer:
To find the volume, we must find the area of the circle and multiply it by its height, think of a cylinder as an object made up of MANY circles. So, V=pir^2h... so diameter is 6cm so radius = 3cm...
therefore, Volume = (pi)(3^2)(12) = 108(pi)
where 12 = height 3 = radius
For the surface area, we need to find the area of the 2 circles(top and bottom ) so once again,
2(pi)(r^2) = 2(pi)(9)
for the area of the rectangle(if we unfold the cylindrical can) we get D(pi)(12) where D= Diameter
so the surface area is
SA = (2)(9)(pi) + 6(pi)(12)
SA = 18pi + 72pi = 90pi
Answer:
%40
Step-by-step explanation:
<u>Step 1: Divide 2/5</u>
2/5 = 0.4
<u>Step 2: Convert to Decimal by multiplying by 100</u>
0.4 * 100 = %40
Answer: %40