Answer:
P = $ 144.99
Step-by-step explanation:
Given data:
cost of home entertainment center is $2665
duration of deferred payment plan is 18 month
interest rate is 24.36%
Total amount to be paid is 

A = 3695.88
From the information in the questioon this amount is to be paid in 3 year . Thus we have
Monthly payment is =

p = monthly payment
Pv = present value = 3695.88
r =rate per period 
n = number of period 
plugging all value in the above formula

P = $ 144.99
Compounded once a year: A=P(1+r)^t
2500=500(1+0.095)^t
1.095^t=5
because the unknown number is an exponent, use log to find the unknown:
log(1.095^t)=log5
tlog1.095=log5
t=log5/log1.095
use your calculator, t=17.734
so this person is about 28 years old.
(12.65) is your total answer because 20/100 x63.25 gives you 12.65
Answer:
I'm not an expert here, this is a best guess!
But I would say if there is no chance that of him incurring excess costs of less than $500, then he knows without insurance he'll end up paying at least $500, possibly more out of pocket, without the insurance.
so I would say He ends up spending the least amount out if pocket by going with option A. for $75. that's $75 out of pocket with no deductible and it covers his $500+ in excess costs....B and C would also cover the excess, but would each cost $140 or $275 out of pocket at the end of the day....
with that being said, I'd say it's worth it to buy the insurance....even if he doesn't have any excess costs, he's spent $75 dollars for the peace of mind to know he's covered either way, and if he does incur the excess costs he's spent $75 rather that $500+....Even if the excess charges are only $100, which it says there is no chance of happening, but still, then he's still saved $25 altogether. Unless I'm reading it wrong, Option A saves him the most money either way, and is worth it to buy the insurance!