An arithmetic sequence has a1 = 5 and a5 = 13. how many terms of this sequence must be added to obtain 60?

Hmmm an arithmetic sequence is done by adding a value to the current term's value to get the next value, the added value is called the "common difference(d)"

so, let's do that to see what it might be then



hmm I was looking how to go about using the Finite Sum equation... I don't see it happening with it though... so... we'd have to add them manually one by one till we get a sum of 60

let's get the term's values then, using d = 2

5 , 7, 9 , 11, 13, 15, 17, 19, 21
                          ^