Guys need help with c, f,g, j

The last time i bought this product , it cost $20.00 but it looks like it cost 29. 60 today? what is the increase

The price of a visit to the dentist is calculated according to the formula 50+100n50+100n where nn is the number of cavities the dentist finds. on your last visit to the dentist, 22 cavities were found. what was the cost of your visit?

Akitchen is 12 ft. by 14 ft. with 10 ft. high walls. how much would it cost to put vinyl flooring in this room? $8.80 per ft