Question

If the sum of simple interest and compound interest at the rate of 8 percent for 2 year is Rs 816 find the principal ​

Answer 1

Given :

Simple interest for two years = 600

Compound Interest for two years = 615

Analysis/Interpretation :

SI for first year = 300

SI for second year = 300

CI for first year = 300

CI for second year = 315

The additional CI of Rs 15 is interest on Rs 300 interest received in first year. So rate of interest is 15/300 x 100 = 5%.

Now, interest of Rs 300 at the end of first year @ 5% pa means principal at the beginning of the year is :

P = 300/5 x 100 = Rs 6000

Note that no formulae for SI or CI is used in the answer and the solution is based on understanding of core concept.

Cheers !!!!!