Jaya and Hema can clean an apartment in 30 days. Hema and Sushma can do the same task in 40 days, while Jaya and Sushma take 60 days to do it. How many days will it take all three of them working together to clean the apartment?

​Jaya and Hema together can clean the apartment in 30 days.

Hema and Sushma together can clean the apartment in 40 days.

Jaya and Sushma together can clean the apartment in 60 days. 

Concept Used: ​

Efficiency = $$\frac{\text{Total Work}}{\text{Days}}$$ 

Solution: ​

Total work is LCM of 30, 40 , 60 = 120 

​