Tap 'a' Can Fill The Tank Completely In 6 Hrs While Tap 'b' Can Empty

1.	Tap 'a' Can Fill The Tank Completely In 6 Hrs While Tap 'b' Can Empty It By 12 Hrs. By Mistake, The Person Forgot To Close The Tap 'b', As A Result, Both The Taps, Remained Open. After 4 Hrs, The Person Realized The Mistake And Immediately Closed The Tap 'b'. In How Much Time Now Onwards, Would The Tank Be Full?
Answer» Tap A can FILL the tank completely in 6 HOURS => In 1 hour, Tap A can fill 1/6 of the tank Tap B can empty the tank completely in 12 hours => In 1 hour, Tap B can empty 1/12 of the tank i.e., In one hour, Tank A and B together can EFFECTIVELY fill (1/6-1/12)=1/12 tank => In 4 hours, Tank A and B can effectively fill 1/12×4=1/3×4=1/3 of the tank. Time taken to fill the remaining (1-1/3)=23(1-13)=2/3 of the tank =(2/3)(1/6)= 4 hours. Tap A can fill the tank completely in 6 hours => In 1 hour, Tap A can fill 1/6 of the tank Tap B can empty the tank completely in 12 hours => In 1 hour, Tap B can empty 1/12 of the tank i.e., In one hour, Tank A and B together can effectively fill (1/6-1/12)=1/12 tank => In 4 hours, Tank A and B can effectively fill 1/12×4=1/3×4=1/3 of the tank. Time taken to fill the remaining (1-1/3)=23(1-13)=2/3 of the tank =(2/3)(1/6)= 4 hours.

Tap 'a' Can Fill The Tank Completely In 6 Hrs While Tap 'b' Can Empty It By 12 Hrs. By Mistake, The Person Forgot To Close The Tap 'b', As A Result, Both The Taps, Remained Open. After 4 Hrs, The Person Realized The Mistake And Immediately Closed The Tap 'b'. In How Much Time Now Onwards, Would The Tank Be Full?

Answer»

Tap A can FILL the tank completely in 6 HOURS

=> In 1 hour, Tap A can fill 1/6 of the tank

Tap B can empty the tank completely in 12 hours

=> In 1 hour, Tap B can empty 1/12 of the tank

i.e., In one hour, Tank A and B together can EFFECTIVELY fill (1/6-1/12)=1/12 tank

=> In 4 hours, Tank A and B can effectively fill 1/12×4=1/3×4=1/3 of the tank.

Time taken to fill the remaining (1-1/3)=23(1-13)=2/3 of the tank =(2/3)(1/6)= 4 hours.

Tap A can fill the tank completely in 6 hours

=> In 1 hour, Tap A can fill 1/6 of the tank

Tap B can empty the tank completely in 12 hours

=> In 1 hour, Tap B can empty 1/12 of the tank

i.e., In one hour, Tank A and B together can effectively fill (1/6-1/12)=1/12 tank

=> In 4 hours, Tank A and B can effectively fill 1/12×4=1/3×4=1/3 of the tank.

Time taken to fill the remaining (1-1/3)=23(1-13)=2/3 of the tank =(2/3)(1/6)= 4 hours.