Angelo has invested 2500 in a longterm savings account that

Angelo has invested $2,500 in a long-term savings account that pays 6.8% annually. How long will it take for his funds to double?

Solution

The rule of 72 states that to determine the approximate amount of time it takes to double your investment at a given rate of return, you simply divide the rate of return by 72.

so here 72/6.8 = 10.5years $2500 amount is doubled in 10.5 years