A city of 4000 has the rate of 25.4 per 2000 people moving into the town while 10.5 per 1000 move out. How long will take for the population to double.  Select the correct option.
A) 10.5  B) 30  C) 133.3  D) 100  E) 1.5
Annual increase is (2000 + 25.4 - 10.4)*2= 
<gadget id="calculator">(2000 + 25.4 - 10.4)*2</gadget>
<output>4_030</output>
4030   Hence every year there is an increase of 30   for the population to double we needs additional 4000   therefore 4000/30=133.3   correct option is 133.3)
<result>C</result>
A city of 4000 has the rate of 25.4 per 2000 people moving into the town while 10.5 per 1000 move out. How long will take for the population to double.