Given: Tap fills the tank in 10 hours. And with the leak tank fills in 11 hours. Formula Used: Efficiency = Total work done / total time taken Total work = LCM of time taken Calculation: Let the tap be 'A' and leak be 'B' Now, Total work = LCM of time taken ⇒ LCM of 10 and 11 As 10 and 11 are co-prime numbers. ⇒ LCM of 10 and 11 = 10 × 11 = 110 Now, Efficiency of tap(A) = 110/10 = 11 Efficiency of leak(A - B) = 110/11 = 10 Efficiency Subject Time taken Total work 11 A 10 110 10 A – B 11 110 ⇒ Efficiency of A = 11 ⇒ Efficiency of A – B = 10 ⇒ Efficiency of B = 1 ⇒ Efficiency of leak(B) = 1 ⇒ Time taken to empty the tank by leakage = 110/1 ∴ Time taken to empty the tank by leakage is 110 hours.