Question of the day 1-11-2016

Question of the day:

Two pipes X and Y can separately fill a cistern in 16 mintues and 24 mintues respectively. If they are turned alternatively for one mintue each, how long will it take to fill the cistern?

a) 18 mintues
b) 19 mintues
c) 20 mintues
d) 21 mintues

Question of the day 31-10-2016

Question of the day :

5, 4, 7, 20, 79, ?