Okay, 16% of $70.00 is $11.20 It says it was compounde 4 times a year for 25 years. 11.2 × 4 = 44.80 Thats how much is collected every year ($44.80) Now multiply $44.80 by 25 years 44.80 × 25 = 1120.00 They compounded $1120.00 in 25 years. Add that to your starting $70.00