e = 2.7182818284590452 (see the 'e' on the calculator?)
So solve this for t (the years the question is asking )
11200 = 5600 e.059t First divide both sides by 5600
2 = e.059t Now take the ln of both sides
.693147181= .059t Now divide both sides by .059 to find t years = 11.78 years ~~ 12 years (rounded)