Question

The simple interest on a certain sum for 2 years is Rs 800,while the compoud interest on the same for 2 years is Rs 820. Find the sum and the rate of interest

Answer 1

All the steps are correct until the last one in the above example
in the very last line
where he calculated the sum t should be substituted with 2 not 1 because 800 is the simple interest of 2 years not 1 year
or else I should have been 400 because the interest for 1 year is 400 not 800
that will give the sum 8000/- and rate 5%
Any way the rest og the steps were absolutely right