Please teach me this i will never forget your help

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

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

What expression is equivalent to log3(x+4)