A sum of money at simple interest amounts to $ 680 in 3 years and to $710 in 4 years. The sum is: Pick one:
A) $153	B) $698	C) $590	D) $549	E) $675
C   $590   S.I. for 1 year = $(710- 680)= 
<gadget id="calculator">(710- 680)</gadget>
<output>30</output>
$30.   S.I. for 3 years= $(30 x 3) = $90.   Principal = $(680 - 90)= 
<gadget id="calculator">(680 - 90)</gadget>
<output>590</output>
$590.
<result>C</result>
A sum of money at simple interest amounts to $ 680 in 3 years and to $710 in 4 years. The sum is: