7500 * 4.2%=315 since its an annual interest rate the 4.2% is paid once a year and its a time period of 2 years so
7500+ 315= 7815 for the first year
7815 * 4.2%= 328.23
7815 + 328.23= 8143.23 for the second year so you then add your 2 years together
7815 + 8143.23 = 15958.23
now round your answer and you get 15958$ in a 2 year period
