Pipe A can fill a tank in 6 minutes and pipe B cam empty it in 24 minutes. If both the pipes are opened together after how many minutes should pipe B be closed, so that the tank is filled in 30 minutes?
Options:
A) 18
B) 27
C) 96
D) 27
E) 21
Let the pipe B be closed after x minutes.   30/6 - x/24 = 1 =&gt; x/24 = 30/6 - 1= 
<gadget id="calculator">30/6 - 1</gadget>
<output>4</output>
4=&gt; x = 4 * 24= 
<gadget id="calculator">4 * 24</gadget>
<output>96</output>
96.   Answer:96
<result>C</result>
Pipe A can fill a tank in 6 minutes and pipe B cam empty it in 24 minutes. If both the pipes are opened together after how many minutes should pipe B be closed, so that the tank is filled in 30 minutes?