Posted by Lizzie on Monday, May 7, 2012 at 2:16am.
In a financial deal, you are promised $800 the first day and each day after that you will receive 45% of the previous day's amount. When one day's amount drops below $1, you stop getting paid from that day on. What day is the first day you would receive no payment and what is your total income?
I am so confused about this problem. Could someone please show me the steps?

Math  Anonymous, Monday, May 7, 2012 at 2:31am
f(day)=800*.45^(day)
Set f(day)=1, solve for day by taking a log on both sides.

Math  Anonymous, Monday, May 7, 2012 at 2:31am
instead of .45^(day) you should actually use .45^(day1) so that the first day is 800

Math  Lizzie, Monday, May 7, 2012 at 3:01am
I tried doing this, but I still have no idea how to solve this problem =/

Math  Reiny, Monday, May 7, 2012 at 8:37am
e.g.
day 1 = 800
day 2 = 800(.45)
day 3 = 800(.45)^2
looks like day (n+1) would be 800(.45)^n
..
when is 800(.45)^n = 1
.45^n = 1/800 = .00125
take log of both sides
log(.45^n) = log .00125
n log .45 = log .00125
n = log .00125/log .45 = 8.3
checking:
day 9 = 800(.45)^8 = 1.35
day 10 = 800(.45)^9 = .61 > receive no income
so he receives income for 9 days
so we want the sum of the geometric series of 9 terms
with a = 800 and r = .45
sum(9) = 800(1  .45^9)/(1  .45)
= 1453.44

Math  Lizzie, Monday, May 7, 2012 at 9:44pm
I understand it now! Thank you so much!

Math  Anonymous, Sunday, January 19, 2014 at 5:30pm
i still don't get it
Answer This Question
Related Questions
 A  You have just landed your first summer job and your boss has told you that ...
 ALGEBRA  You have just landed your first summer job and your boss has told you ...
 biology  time day 0 day 1 day 3 day 4 day 5 day 7 count blank 7 10 5 14 9 8 low...
 Math  1. Daniel wants to save at least 20 dollars by putting pennies in a jar ...
 Math  Bill is saving money in an empty jar. The first day he puts in a certain ...
 maths  challenge  Simon starts a new job . On the first day he gets paid 1p . ...
 math  each day Ashley practices free throws. The first day she takes 12 shots, ...
 math  On first day you receive 1 cent on the second day 2 cents on the third ...
 Algebra  Stella is recording temperatures every day for 5 days. On the first ...
 math  Imagine that I am hiring you to work for me for the next month (30 days...
More Related Questions