Answer:
Step-by-step explanation:
Amount of brine = 100 gal
amount of salt = 80 lb
rate of water running = 4 gal / min
Let A be the amount of salt in lb in the tank at any time t.
(a) dA/dt = rate of salt in - rate of salt out
Rate of salt in = 0
rate of salt out = A x 4 / 100 = A / 25 lb/min
So, dA/dt = 0 - A/25 = - A/25 lb/min



When t = 0, A = 80 lb
So,

(b) Now, A = 40 lb
So,


take log on both the sides

t = 17.3 minutes
Correction from my spelling,
If she walks from A to C to B*
If you have any question upon my solution, please ask !
Hope this helps you :)
Answer:
-14
Step-by-step explanation:
You've got a(1)=20
a(1) means a(n) when n=1
the sequence is telling you to take the previous value of a(n), which is a(n-1) and subtract 17
then:
a(2) = a(1)-17 = 20 - 17 = 3
a(3) = a(2) - 17 = 3-17 = -14
Take the natural log of both sides
ln(2^x)=ln(.125)
Xln(2)=ln(.125)
X=ln(.125)/ln(2)
X=-3
ALTERNATIVE ROUTE:
You know that 0.125 is equal to 1/8
And 1/2^3 is also equal to 1/8
So since you need the reciprocal to match it the exponent is a negative
Answer:
18km/[unit of time]
Step-by-step explanation:
v (speed) = d/t
v = 198/11
v = 18