30. Given problem : You deposited 2 000 dollars, then you will earn 6% simple interest. Question: How long will it become 2 600 dollars. Well, you didn’t mention if it’s an annual interest or monthly interest. But let’s say that it’s a monthly interest, then let’s start solving: => 2000 Is the original amount + 6% interest first month = 2000 * .06 = 120 => 2000 + 120 = 2120 2nd month = 2120 *.06 = 127.2 => 2120 + 127.2 = 2247.2 3rd month = 2247.2 *.06 = 134.832 => 2247.2 + 134.832 = 2382.032 4th month = 2382.032 * .06 = 142.92192 => 2382.032 + 142.92192 = 2524.95392 5th month = 2524.95392 * .06 = 151.497 => 2524.95392 + 151.497 = 2676.45 Thus, on the fifth month she will earn this amount.