Answer:
15 years
Step-by-step explanation:
Use the FV formula to calculate the total duration;
Future value ; FV= 52,421
Present value; PV = 19,000
Interest rate ; r = 7% of 0.07 as a decimal
Total duration ; t = ?

Divide both sides by 19,000;

Introduce logarithm on both sides;
㏑2.759 = t㏑1.07
Divide both sides by ㏑1.07 to solve for t;
㏑2.759 / ㏑1.07 = t
t = 14.9998
Therefore, it will take 15 years