Just the Mountain bike, cause 4% of $2000 is, $80. and $80 for each year for 7 years make $560. now after 7 years your bank account has $2560. Therefore, you can buy a mountain bike, and have $60 left over, if there is no tax included. But if there is tax, your going to be still short by $115.(calculated according to florida's tax, that is 7%.) Anyways if the tax is over 2% you cant get that bike.
and it would be divide by 3.14 (pi) and then you should have the diameter. Then divide by 2 to find radius.