3. A sum of money lent out at C.I. at a certainrate per annum becomes three times of itselfin 8 years. Find in how many years will themoney become twenty-seven times of itself atthe same rate of interest pa.

3. A sum of money lent out at C.I. at a certainrate per annum becomes

1.	3. A sum of money lent out at C.I. at a certainrate per annum becomes three times of itselfin 8 years. Find in how many years will themoney become twenty-seven times of itself atthe same rate of interest pa.
Answer» Let the sum of money be Rs P and the rate of interest be r % p.a.Amount at the end of 8 years = Rs 3PFormula for amount= P(1+(r/100))^nwhere n=time,p=principal and r=rate3P=P(1+(r/100))^83=(1+(r/100)^8 .............1Let the money becomes 27 times in n years 27P=P(1+(r/100))^n27=1+(r/100))^n(3)^3=1+(r/100)^n(1+(r/100))^8)^3=1+(r/100))^n from 11+(r/100))^24=1+(r/100)^nComparing bases we getn=24 years