A sum of money at simple interest amounts to Rs. 835 in 3 years and to Rs. 854 in 4 years. The sum is:	Choose the correct choice from the following options
A) 647
B) 698
C) 778
D) 847
E) 976
S.I. for 1 year = Rs. (854 - 835) = Rs. 19.   S.I. for 3 years = Rs.(19 x 3) = Rs. 57.   Principal = Rs. (835 - 57) = Rs. 778.   Answer:778
<result>C</result>
A sum of money at simple interest amounts to Rs. 835 in 3 years and to Rs. 854 in 4 years. The sum is: