Posted by John on Sunday, August 7, 2011 at 11:13pm.
Can you please explain step by step on how to do each of these two problems below? And then tell me whether it involves an arithmetic sequence or a geometric sequence I also need the work shown out for both problems thank you.
1). A person hired a firm to build a CB radio tower. The firm charges $100 for labor for the first 10 feet. After that, the cost of the labor for each succeeding 10 feet is $25 more than the preceding 10 feet. That is, the next 10 feet will cost $125, the next 10 feet will cost $150, etc. How much will it cost to build a 90foot tower?
2). A person deposited $500 in a savings account that pays 5% annual interest that is compounded yearly. At the end of 10 years, how much money will be in the savings account?

Math  Reiny, Monday, August 8, 2011 at 7:22am
ost = 100 + 125 + 150 + 175 + for 9 terms
This is an arithmetic series
a = 100
d = 25
n = 9
Sum(9) = (9/2)(2(100) + (91)(25))
= (9/2)(200 + 200) = 1800
2)
amount = 500(1.05)^10 = 814.45 
Math  michelle, Sunday, August 14, 2011 at 1:54pm
what is the arithmetic oe 3,5,7,9,and 11

Math  cathyj, Sunday, March 25, 2012 at 8:00pm
Mary has been working at the university for 25 years, with an excellent record of service. As a result, the board wants to reward her with a bonus to her retirement package. They are offering her $75,000 a year for 20 years, starting one year from her retirement date and each year for 19 years after that date. Mary would prefer a onetime payment the day after she retires. What would this amount be if the appropriate interest rate is 7%?