The simple interest on a certain sum of money for 2 l/2 years at 12% per year is Rs. 40 less than the simple interest on the same sum for 3 ½ years at 10% per year. Find the sum.
Choose the correct choice.
A) 800
B) 700
C) 600
D) 500
E) None of them
Let the sum be Rs. x Then, ((x*10*7)/(100*2)) – ( (x*12*5)/(100*2)) = 40   = (7x/20)-(3x/10)=40   x = (40 * 20)= 
<gadget id="calculator">(40 * 20)</gadget>
<output>800</output>
800.   Hence, the sum is Rs. 800.   800nswer is 800.
<result>A</result>
The simple interest on a certain sum of money for 2 l/2 years at 12% per year is Rs. 40 less than the simple interest on the same sum for 3 ½ years at 10% per year. Find the sum.