A sum of money lent out at S.I. amounts to Rs. 850 after 2 years and to Rs. 1020 after a further period of 5 years. The sum is?  Choose the correct choice from the following choices
A) s.440
B) s. 500
C) s. 540
D) s. 782
E) s. 840
S.I for 5 years = (1020 - 850) = Rs. 170.   S.I. for 2 years = 170/5 * 2 = Rs. 68.   Principal = (850 - 68) = Rs. 782.   ANSWER:s. 782
<result>D</result>
A sum of money lent out at S.I. amounts to Rs. 850 after 2 years and to Rs. 1020 after a further period of 5 years. The sum is?