Anu normally takes 4 hours more than the time taken by Sachin to walk D km. If Anu doubles her speed, she can make it in 2 hours less than that of Sachin. How much time does Sachin require for walking D km?  Choices:
A) 10 hours	B) 4 hours	C) 8 hours	D) 9 hours	E) None
Explanation :   Let Sachin takes x hours to walk D km.   Then, Anu takes (x + 4) hours to walk D km.   With double of the speed, Anu will take (x + 4)/2 hours.   x – (x + 4)/2 = 2    (  + 4)/2= 
<gadget id="calculator"> (  + 4)/2</gadget>
<output>2</output>
2=&gt; 2x – (x + 4) = 4    (  + 4)= 
<gadget id="calculator"> (  + 4)</gadget>
<output>4</output>
4=&gt; 2x – x – 4 = 4   x = 4 + 4= 
<gadget id="calculator">4 + 4</gadget>
<output>8</output>
8 hours   Answer – 8 hours
<result>C</result>
Anu normally takes 4 hours more than the time taken by Sachin to walk D km. If Anu doubles her speed, she can make it in 2 hours less than that of Sachin. How much time does Sachin require for walking D km?