2 pipes can separately fill a tank in 20hrs and 30hrs respectively. Both the pipes are opened tofill the tank, a leak develops in the tank through which one-third of water supplied by both the pipes goes out. What is the total time taken to fill the tank?  Choose the most appropriate option:
A) 10 hrs
B) 12 hrs
C) 16 hrs
D) 18 hrs
E) 20 hrs
1/20 + 1/30 = 1/12   1 + 1/3 = 4/3   1 --- 12   4/3 --- ?     4/3 * 12= 
<gadget id="calculator">  4/3 * 12</gadget>
<output>16</output>
16 hrs   16 hrs
<result>C</result>
2 pipes can separately fill a tank in 20hrs and 30hrs respectively. Both the pipes are opened tofill the tank, a leak develops in the tank through which one-third of water supplied by both the pipes goes out. What is the total time taken to fill the tank?