Find last years salary if, after a 5% pay raise, this year's salary is $40,425

This race was first held in 1953 on august 16th. every decade the race finishes with a festival. how many years is this?

I’m stuck on this equation, anyone got the answer?

Diane’s bank is offering 5% interest, compounded monthly. if diane invests $10,500 and wants $20,000 when she withdrawals, how long should she keep her money in for? round to the nearest tenth of a year.