15. If the sum of an infinite series is 130 and the common ratio is -, determine t, and the first three terms of the series. If an answer is not a whole number, round to the nearest tenth. (3 marks) 16. Determine the sum of each series. If an answer is not a whole number, round to the nearest tenth. (6 marks) a. 1-3+9-...-243 b. -72+36-18+... (first 8 terms) c. 6.1+1.22+0.244 +0.0488 +