Answer:
13years
Step-by-step explanation:
Using the formula for calculating the compound interest expressed as;
A =P(1+r)^n
P = 12000
rate r = 4% = 0.04
Amount after 4 years A = 20,000
Substitute into the formula and solve for p
20,000 = 12,000(1+0.04)^t
20,000/12000 = (1.04)^t
1.67 = (1.04)^t
Take the ln of both side
ln1.67 = ln(1.04)^t
ln1.67 = t ln 1.04
t = ln1.67/ln1.04
t = 0.5108/0.0392
t = 13.03
hence it will take approximately 13years to reach 20,000
