A savings account was set up where payments of $150 were made each month starting on May 20, 2010. Interest rates changed as follows: In the year 2010, interest was 9% annual interest compounded monthly. In the years 2011-2013, interest was 9.6% annual interest compounded monthly. Since 2013, interest has been 10% annual interest compounded monthly. Calculate the amount in the account and the interest earned at each of the following dates:

a. April 20, 2012

b. April 20, 2015