Exams

Let the efficiencies of filling pipes is 4p and 5p respectively.

Efficiency of pipe which empty the tank = 2/3 x 9p/2 = 3p

Total work = 3p x 36 = 108p

Time to fill the tank by both the pipes = 108p/9p = 12 min.

OKG
Remaining all are not in series
only OKG is in series of(15,11,7)

Here it follows the random difference of '4'.

A Libraury. It has more number of story books in it to read.

Facilitate means assist someone in their progress or work. Here Help is the only word which is similar in meaning with facilitate. Halt and check are antonyms i.e opposite in meaning of facilitate. 

Hence, facilitate is similar in meaning to help.

Second ozone hole was detected over Tibet in the year 2006. 

Ozone is a form of oxygen, acts as a high-altitude atmospheric screen against cancer-causing ultraviolet light.

The main source of these halogens in the stratosphere is photodissociation of man made halocarbon refrigerants, solvents, propellants and CFC's.

A place where honey bees are kept in called an Apiary or a bee yard.

In Indian History, Dandi March or Salt Sathyagraha or The Salt March, also known as the Dandi Satyagraha, was an act of nonviolent civil disobedience in colonial India led by Mohandas Karamchand Gandhi to produce salt from the seawater. 

It is also called as 'White Flowing River'.

% Decrease in Width = 50150x100

= 33.33%