(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In an arithmetic progression, the sum of the first 10 terms is the same as the sum of the next 5 terms. Given that the first term is 12, find the sum of the first 15 terms.

2.

The only one I could think of is

S= n/2 (2a+(n-1)d)

3.

I've tried solving it, but failed. I guess this is due to lack of experience, as I missed the topic.

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# Homework Help: Arithmetic progression

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