Answer:
Week 1: 10 Minutes
Week 10: 77.5 Minutes or 1 hour and 17.5 Minutes
Week n: 10 + 7.5n
Step-by-step explanation:
Every week, Greg adds another 7.5 minutes to his workout time. Week 1 starts off with 10 minutes and continuously adds 7.5 minutes until he gets to week three, which 10 + 7.5(2) = 25 minutes.
Answer:
50 quarters and 28 nickels
Step-by-step solution:
We have two variables we are solving for. We will call them Q for the number of quarters and N for the number of nickels.
We know that the total number of coins is equal to 78, and we know that the total amount the coins are worth is equal to $13.90. With this information, we can set up a system of equations:
Q + N = 78
0.25Q + 0.05N = 13.90
Now we can solve for either Q or N in the first equation and solve by substitution by plugging the value into the second equation. Let's solve for Q:
Q = 78 - N
Now plug in 78-N for Q:
0.25(78-N) + 0.05N = 13.90
Distribute and combine like terms:
19.50 - 0.25N + 0.05N = 13.90
19.50 - 0.20N = 13.90
-0.20N = -5.60
N = 28
Now we know that there are 28 nickels. We can plug this into one of the original equations to solve for Q:
Q + 28 = 78
Q = 50
There are 50 quarters. We can verify our answer by plugging the values for A and N into the other equation (optional step to check work):
0.25(50) + 0.05(28) = 13.90
12.5 + 1.40 = 13.9
13.9 = 13.9
Our answer is correct.
Answer:
a. dQ/dt = -kQ
b. 
c. k = 0.178
d. Q = 1.063 mg
Step-by-step explanation:
a) Write a differential equation for the quantity Q of hydrocodone bitartrate in the body at time t, in hours, since the drug was fully absorbed.
Let Q be the quantity of drug left in the body.
Since the rate of decrease of the quantity of drug -dQ/dt is directly proportional to the quantity of drug left, Q then
-dQ/dt ∝ Q
-dQ/dt = kQ
dQ/dt = -kQ
This is the required differential equation.
b) Solve your differential equation, assuming that at the patient has just absorbed the full 9 mg dose of the drug.
with t = 0, Q(0) = 9 mg
dQ/dt = -kQ
separating the variables, we have
dQ/Q = -kdt
Integrating we have
∫dQ/Q = ∫-kdt
㏑Q = -kt + c

when t = 0, Q = 9

So, 
c) Use the half-life to find the constant of proportionality k.
At half-life, Q = 9/2 = 4.5 mg and t = 3.9 hours
So,

taking natural logarithm of both sides, we have
d) How much of the 9 mg dose is still in the body after 12 hours?
Since k = 0.178,

when t = 12 hours,

Since the order of the books chosen doesn't matter, we use the combination formula to find the number of possible selections. Recall that a combination of k items from a set of n items is given by

.
In this problem, n = 8 and k = 3. So the number of possible selections is

. Thus the answer is 56.
Answer:
C. 2,589.25
Step-by-step explanation:
Salary=$3500
Less:
Federal income withheld
15% of $3500
=15/100×$3500
=$525
Social security tax of 6.2%
6.2% of $3500
=6.2/100 × $3500
=$217
Medicare tax of 1.45%
1.45% of $3500
1.45/100 × $3500
=$50.75
Health insurance premium=$48
Savings plan of 2%
2% of $3500
=2/100 × $3500
=$70
Total less:= $525 + $217 + $50.75 + $48 + $70
Eric's net pay =$3500 - $910.75
=$2,589.25