A sum of money at simple interest amounts to $ 700 in 3 years and to $764 in 4 years. The sum is: Pick one.
A) $508
B) $698
C) $398
D) $549
E) $675
A   $508   S.I. for 1 year = $(764 - 700)= 
<gadget id="calculator">(764 - 700)</gadget>
<output>64</output>
$64.   S.I. for 3 years= $(64 x 3) = $192.   Principal = $(700 - 192)= 
<gadget id="calculator">(700 - 192)</gadget>
<output>508</output>
$508.
<result>A</result>
A sum of money at simple interest amounts to $ 700 in 3 years and to $764 in 4 years. The sum is: