Question

How many terms in the sequence 18,16,14...should be taken so that their sum is zero

Answer 1

Well, assuming that you mean all the terms added together, it would have to go until -18 so that the numbers cancel each other out. To get to 0 from 18, going down by two, it would take 10 terms. To get to -18 from 0, it would also take 10 terms. In the end, it takes 20 terms for the sum of all of them to equal 0. Hopes this helps!