A certain sum becomes Rs. 6400 in 4 years and Rs. 8200 in 7 years at simple interest. Find the pricipal.

A certain sum amounts to Rs. 4800 in 4 years and to Rs. 5250 in 5 years at simple interst. Find the interest for 2 years.

A sum becomes Rs. 10650 in 5years and Rs. 11076 in 6 years at simple interest. What is the sum ?

A certain sum of money amounts to Rs 4200 in 3 years and to Rs 6000 in 6 years at simple interest. Find the rate of interest.

A certain sum amounts to Rs 73,255 in 3 years, and Rs 84,525 in 5 years at simple interest. Find the sum.

A certain sum becomes Rs. 2400 in 10 years at the rate of 2% per annum under simple interest. Find the sum.