How many years will it take to double an investment at 11% simple interest?

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)