Question

_{You invest $150 in a mutual fund today that pays 9 percent interest annually. How long will it take to double your money? (If you solve this problem with algebra round intermediate calculations to 6 decimal places, in all cases round your final answer to 0 decimal place, e.g. 545) Number of years}

Answer 1

Number of years it will take to double the money is:-

=NPER(rate,pmt,pv,fv)

=NPER(9%,,-150,300)

=8.04 or 8 years or if the years are to round off to the next bigger number then answer will be 9.

Answer 2

SOLUTION :

FV / PV = (1 + r)^n

=> 2 = (1 + 0.09)^n = 1.09^n 

Taking log :

log(2) = n log(1.09)

=> n = log(2)/log(1.09)

=> n = 8.04 years (ANSWER)