Verbal Reasoning - Mental Ability Questions

The arithmetic mean of the following numbers 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6 and 7, 7, 7, 7, 7, 7, 7 is   ?

Four subjects — Physics, Chemistry, Mathematics and Biology were taught in four consecutive periods of one hour each starting from 8.00 a.m. At what time was the Chemistry period scheduled ?  

I. Mathematics period ended at 10.00 a.m. which was preceded by Biology. 

II. Physics was scheduled in the last period. 

III. Mathematics period was immediately followed by Chemistry. 

Which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?

 ___ utt ___ tt ___ ttu ___   

Dilatory : Expeditious :: Direct : ?

Minute is to hour as second is to

Assertion(A) : The pouring of kerosene oil on stagnant pools helps to eradicate malaria.
Reason(R) : The kerosene oil is poisonous for the mosquitoes.

Hydrogen is lighter than Hydrogen .Hydrogen is lighter than helium.Therefore,Oxygen is the heaviest of the three gases

If all the letters in the word  MERCIFUL are rearranged in alphabetical order and substituted by the alphabet preceding them in the English alphabet. What will be the new arrangement of letters?