Given P=Rs. 25,000, A=Rs. 42,127.50 and R=11%, we have to find time n. Using compound interest = A−P, we get Rs.42,127.50−25,000=Rs.17,127.50 as compound interest.
Thus, Rs.17,127.5 is the compound interest for Rs.25,000 at 11%.
Now, we find the compound interest for Rs. 1. For the principal Rs.25,000, the compound interest is Rs.17,127.5.
For the principal Rs. 1, the compound interest is 17,127.525,000=0.6851.
Now, refer to the table corresponding to the column with 11%. Here 0.6851 corresponds to 5 years.
Hence, the period is 5 years.