Verbal Reasoning - Mental Ability Questions

There are two examinations rooms P and Q. If 10 students are sent from P to Q, then the number of students in each room is the same. If 20 candidates are sent from Q to P, then the number of students in P is double the number of students in Q. The number of students in room Q is ?

O and O' are the center of the two circles with radii 7cm and 9cm respectively. The distance between the centers is 20cm. If PQ be the transverse common tangent to the circles, which cuts OO' at X, what is the length of O'X in cm ?

Mathematics : Numbers :: History : ?

If [P @ Q] means [P is wife of Q], [P+Q] means [P is father of Q] and [P - Q] means [P is sister of Q] then in [G+ H - R @ D], how is G related to D ?

If three groups could be formed using the given figures only once, these groups would be ___.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

If the first half of the given alphabets are written in reverse order which letter should be 8th letter to the left of 14th letter from the right?

In the following question, various terms of an alphanumerical series are given with one or more terms missing as shown by (?). Choose the missing terms out of the given alternatives. 3F, 6G, 11I, 18L, ?

If the letters of the word OBSERVANT are interchanged, such that the first becomes ninth, second becomes eighth and so on, and the position of the fifth letter remains unchanged then what will be the new arrangement of letters?