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
Answer: N=800/5
N=160
He needs to save $160 every week to get $800 in 5 weeks
hope this helps.
You subtract normally inside the absolute value (the two bars):
-4-3 is -7
Since the negative is INSIDE the absolute, the answer will turn to a positive. Think of the bars as a jail cell for the negatives. Once the negatives are in there, only positive numbers will come out. So your answer is 7.