Hi

2 question i want check the answer .

http://www12.0zz0.com/2010/03/05/06/207886290.jpg

http://www10.0zz0.com/2010/03/05/18/277725831.jpg

thanks

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- March 5th 2010, 10:27 AMr-soy2 question i want check the answer .
Hi

2 question i want check the answer .

http://www12.0zz0.com/2010/03/05/06/207886290.jpg

http://www10.0zz0.com/2010/03/05/18/277725831.jpg

thanks - April 23rd 2010, 05:58 AMmr fantastic
- April 23rd 2010, 10:55 PMpflo
You are correct that these are both questions about arithmetic series. But your formulas are incorrect so your answers are wrong. You need a better undersanding of what each term of the formulas actually do. Anyway, here are the correct formulas:

In both problems, you know the sum as well as and . You can plug the first formula into the second to get rid of the , which would make the only variable. In solving the equation for , you should see that it is a quadratic equation: . The simpliest way to solve these will be by using the quadratic formula.

The answers I get are 20 months and 5 years. - April 24th 2010, 01:19 AMWilmer
- April 24th 2010, 06:04 AMpflo
- April 24th 2010, 07:00 AMWilmer
Yes, I realise that Pflo; wanted to make sure R-soy realised it too:

he has 79.2268 and 43, quite a ways off.