Question 933471
You have this arithmetic sequence

1, 2, 3, 4, ..., 28, 29, 30


The first term is 1, the last term is 30. There are 30 terms. So,


a1 = 1
an = 30
n = 30


Use the arithmetic sequence partial sum formula


Sn = n*(a1+an)/2


to get


Sn = n*(a1+an)/2


Sn = n*(1+30)/2


S30 = 30*(1+30)/2


S30 = 465


So she has 465 dimes. Convert to dollars


(465 dimes)*(1 dollar/10 dimes) = 465/10 = 46.50 dollars


So the answer is choice D.

------------------------------------------------------------------------------------------------------------------------


If you need more one-on-one help, email me at <a href="mailto:jim_thompson5910@hotmail.com?Subject=I%20Need%20Algebra%20Help">jim_thompson5910@hotmail.com</a>. You can ask me a few more questions for free, but afterwards, I would charge you ($2 a problem to have steps shown or $1 a problem for answer only).


Alternatively, please consider visiting my website: <a href="http://www.freewebs.com/jimthompson5910/home.html">http://www.freewebs.com/jimthompson5910/home.html</a> and making a donation. Any amount is greatly appreciated as it helps me a lot. This donation is to support free tutoring. Thank you.


Jim

------------------------------------------------------------------------------------------------------------------------