I found this quite interesting:

A loan of $3000 over 24 months is obtained.

The rate will be 9% annual compounded monthly for the 1st year,

then 12% annual compounded monthly for the 2nd year.

What is the required monthly payment over the 24 months?

Part 2:

a = 3000, u = .09/12, v = .12/12, p = monthly payment

What is p in terms of a,u,v ?