Answer:
Step-by-step explanation:you just subtract or multiply the percent
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
Well, first you should make both sides of the equation to the power of 2.
So, you'll have 7X = 1225, and then X is 175 :)
Have a wonderful day!
Let dimes = d and quarters =q
D + q = 50
D= 50-q
0.10d + 0.25Q = 7.70
Replace d with 50-q:
0.10(50-q) + 0.25q = 7.70
Simplify:
5 -0.10q + 0.25q = 7.70
5 + 0.15q = 7.70
Subtract 5 from both sides:
0.15q = 2.70
Divide both sides by 0.15:
Q = 2.70 / 0.15
Q = 18
D = 50-18 = 32
There are 32 dimes and 18 quarters