Answer:
10 years
Step-by-step explanation:
We can use the equation for simple interest: I = P(1 + (R*T)), and change some of the numbers: 2P = P(1 + (0.11*T))
Divide: 2 = 1 + (0.11*T)
Subtract: 1 = 0.11*T
Divide: T = 100/11 ≈ 9.09 ⇒ 10 years (rounded up because it won't be doubled until the next year)