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
Step-by-step explanation:
5x-7+3x+27=180
8x+20=180
8x=160
x=20°.
hope this helps you.
Answer:
14.49272 or 14.5 (when rounded)
Step-by-step explanation:
Divide 1681 by 4 which is about 420.25 feet for length
Answer:
The amount to be repaid is $379.26.
Step-by-step explanation:
Period of note from May 1 to December 19 = 233 days
Amount of note or principal = $1,000
Simple interest rate = 8.5%
Maturity date = December 19
Repayments:
June 2 = $475
Nov. 4 = $200
Total paid $675
Simple interest = $54.26 ($1,000 * 8.5% * 233/365)
Total amount to be repaid = $1,054.26
Total amount repaid = 675.00
Balance to be paid on maturity $379.26
