we know that
The simple interest formula is equal to
\(F=P*(1+n*r)\)
where
F is the future value
P is the present value
n is the number of years
r is the annual interest rate in decimal
In this problem
we have
\(P=\)$@@MATH_TOKEN_2@@
@@MATH_TOKEN_3@@% -----> @@MATH_TOKEN_4@@
@@MATH_TOKEN_5@@$\(10,000\)
Find the value of n
\(F=P*(1+n*r)\\ \\ \frac{F}{P} =1+n*r\\ \\ n=\frac{(\frac{F}{P}-1)}{r} \\ \\ n=\frac{(\frac{10,000}{3,900}-1)}{0.0783}\\ \\ n=19.98 years\)
therefore
the answer is the option
\(c. 20 years\)
