Answer:
The principal will double in 3 years and 3 months
Step-by-step explanation:
the current balance is the Principal. The bank will apply this 24% rate for now on, we need to determinate the time at which the amount owed is 2 principals:

We convert the residual in months:
0.22 x 12 = 2.66
We detemrinate that n will be 3 years and almost 3 months