17. A sum of money at simple interest amounts to Rs.720 after 2 years and to Rs.1020 after a further period of 5 years. The sum is :
Answer:
S.I. for 5 years = Rs.(1020-720) = Rs.300
S.I. for 2 years = Rs.(300/5)*2 = Rs.120.
Therefore, Principal = Rs.(720-120) = Rs.600.
