A sum at a certain rate of simple interest becomes ₹14880 after 3 years and ₹16800 after 5 years. Find the simple interest on the same sum at 10%per annum for 4 years (in ₹).

4800

Principal becomes Rs 14880 after 3 years and Rs 16800 in 5 years

Interest for 2 years = 16800-14880

                             = 1920

Interest for 1 year = \(\frac{1920}{2}\)

                            = Rs 960

Interest for 3 years = 960 × 3

                            = Rs 2880

Principal = Amount - Interest

= 14880- 2880

= 12000 Rs

Now

Principal(P)=Rs 12000

Time(T)= 4 years

Rate  = 10 %

Interest(I)=\(\frac{P×R×T}{100}\) 

Interest(I)=\(\frac{12000×10×4}{100}\)

Interest(I)=Rs 4800