Algebra
posted by mysterychicken .
I'm really stuck on these 2. Can you please explain the work clearly so that I can understand and find the answer easily, if already not given.
Need help with these 2 please
19. Nancy invests $100 in one account for 10 years at a 9% interest rate compounded annually, and she invests $150 in an account for 10 years at a 6% interest rate compounded semiannually. How much money will she have in the accounts after 10 years?
20. Suppose Tyler sprayed around the house for ants. Which formula would be used to find the number of ants still alive after a certain time if the number of ants was changing exponentially?
a. a = P(o.56)^t
b. y = mx + b
c. a = x
d. a = P(1.23)^t
Thanks
MC

19. Pt=Po(r+1)^n =100(1.09)^10=236.74
n=the number of compoundingperiods.
r=Rate per compounding period=APR.
Po=amount invested.
Pt=amount at 10 yrs.
Pt=150(1.03)^20=270.92
TOTAL=236.74++270.92=507.16
20. The correct choice is d.
a is not the correct choice,becaus
when a number less than one is
raised to a power ,it decreases.