Answer:
Step-by-step explanation:
Given that a large mixing tank initially holds 400 gallons of water in which 70 pounds of salt have been dissolved. Pure water is pumped into the tank at a rate of 4 gal/min, and when the solution is well stirred, it is then pumped out at the same rate.
Let Q(t) be the quantity of salt at time t.
Q(0) = 70 pounds
Inflow of water = outflow = 4 gal/min
So resulting volume of tank at time t = 400 gallons
Rate of change of salt = inflow - outflow
= 0 - 
i.e. 
This is a variable separable equation

Use when t =0 Q = 70
A =70
So A(t) = Q(t) =
and
A(0) = Q(0) = 70 lbs.
wheee
Compute each option
option A: simple interest
simple interest is easy
A=I+P
A=Final amount
I=interest
P=principal (amount initially put in)
and I=PRT
P=principal
R=rate in decimal
T=time in years
so given
P=15000
R=3.2% or 0.032 in deecimal form
T=10
A=I+P
A=PRT+P
A=(15000)(0.032)(10)+15000
A=4800+15000
A=19800
Simple interst pays $19,800 in 10 years
Option B: compound interest
for interest compounded yearly, the formula is

where A=final amount
P=principal
r=rate in decimal form
t=time in years
given
P=15000
r=4.1% or 0.041
t=10


use your calculator
A=22418.0872024
so after 10 years, she will have $22,418.09 in the compounded interest account
in 10 years, the investment in the simple interest account will be worth $19,800 and the investment in the compounded interest account will be worth$22,418.09
Answer:
Step-by-step explanation:
A, B and C must be real numbers, and A and B are not both zero (which would cause division by zero in the calculation of the slope).