A reduction of 20% in the price of salt enables a lady to obtain 10kgs more for Rs.400, find the original price per kg?	Choose the most appropriate option:
A) s.7	B) s.9	C) s.10	D) s.11	E) s.19
100*(20/100)= 
<gadget id="calculator">100*(20/100)</gadget>
<output>20</output>
20 --- 10   ? --- 1=&gt; Rs.2   400 --- 80   ? --- 2 =&gt; Rs.10   Answer:s.10
<result>C</result>
A reduction of 20% in the price of salt enables a lady to obtain 10kgs more for Rs.400, find the original price per kg?