The time is 2 years:
Important variables to know:
A= Amount
P = Principal
I = simple Interest
T = time in years
R = rate in years
Formulas:
A = P + I
I = PRT
What we have? Amount ($512), Principal ($400), Rate (14%)
What we need? Time and Interest (simple interest)
So, first let's find the interest.
512 = 400 + I
Subtract 400 from both sides.
I = 112
Then plug that into the second formula:
112 = 400*.14(T)
Multiply 400*.14= 56
112 = 56T
Divide both sides by 56
T = 2 years
