ti cant even find out the answer without that upgrade thing there. Please remove it it is really annoying. I am very sorry but i hate watching the video just to skip it. I do know that this is not a question but thank you.

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is