Show work and explain with formulas if possible.

12. you enlarge a photo to 150% of its previous size several times. if the photo measures 4 inches in length after the first increase, how long is it after 5 increases?

13. larry exercised every day for 30 days. the first day he did 8 sit-ups, the 2nd day he did 12 sit-ups, the 3rd day he did 16 sit-ups, etc. after the 30th day of exercising, what was total number of sit-ups that larry had done?

16. write the first three terms of the series and then evaluate the sum of the series. (see picture)