2 years. To work out 4% of $2500, you divide it by ten (250). This gives you 10%. Then you divide it by 2 (125) which gives you 5%. To work out 4% you need to take 1% of 5%. To work out 1% you divide 2500 by 100 which is 25. Then you take it away from 125 which equals 100. To earn $200 interest, it would take to years because 100*2=200
