what is 3a?

Problem 3: Calculating Interest Rates. For each of the following, solve for the unknown interest rate: 3 b c 3d Present Value ($) Years -500.00 4 -675.00 9 -12,500.00 12 -55,000.00 24 Interest Rate ? ? ? ? Future Value ($) 600.00 1,200.00 85,000.00 1,200,000.00 Points 2.5 2.5 2.5 2.5