Question 840601
tank filled by pipe 1 in 1 min = 1/10
tank filled by both pipe in 1  min = 1/6
tank filled by second pipe in 1 min be  1/x
then, 1/10+1/x=1/6
1/x=1/6-1/10
1/x = 2/30
1/x =1/15
Therefore time taken by pipe 2 to fill the tank is 15 mins