3 pumps, working 8 hours a day, can empty a tank in 2 days. How many hours a day must 15 pumps work to empty the tank in 1 day?
Answers.
A) 3.5
B) 4.8
C) 5.1
D) 5.2
E) 6.3
3 pumps take 16 hrs total (8 Hrs a day)   If 1 pump will be working then, it will need   16*3= 
<gadget id="calculator">  16*3</gadget>
<output>48</output>
48 hrs   1 pump need 48 Hrs   If I contribute 15 pumps then   48/15=3.5 hrs.   answer :3.5
<result>A</result>
3 pumps, working 8 hours a day, can empty a tank in 2 days. How many hours a day must 15 pumps work to empty the tank in 1 day?