Pipe L alone can fill a tank in 40 minutes while L and M together can fill the same tank in —— minutes. Pipes M and N together can fill the tank in 30 minutes. If pipes L and N are opened together such that pipe N works at —— % of its original efficiency, then the tank can be filled in 48 minutes. 

Which among the following given below contains the values that will fill the blanks in the same order so as to make the statement true?

I) 24, 20%

II) 15, 50%

III) 18, 25%