Let X = {Ram, Geeta, Akbar} be the set of students of Class XI, who are in school hockey team. Let Y = {Geeta, David, Ashok} be the set of students from Class XI who are in the school football team. Find `X ∪ Y` and interpret the set.

Let U be universal set of all the students of Class XI of a coeducational school and A be the set of all girls in Class XI. Find A′.

Let A be the set of all 50 students of Class X in a school Let f: A to N be function defined by f(x) = roll number of the student x. Show that f in one-one but not onto.

Let A be the set of the children in a family. The relation ‘x is a brother of y' relation on A is

Let A be the set of all students of a boys school. Show that the relation R in A given by R = {(a,b):a is sister of b} is the empty relation and R' ={(a,b): the difference between heights of a and b is less than 3 meters } is the universal relation.

Form the pair of linear equations in the following problems, and find their solutions. 10 students of Class X took part in a Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of boys and girls who took part in the quiz.

Yamini and Fathina, two students of class IX of a school, together contributed Rs. 100 toewards the prime minister relief fund to help the earthquake victims. Write a linear equation which satisfies this data. (You may take their contribution as Rs. x and Rs. y) Draw the graph of the same.

Make correct statements by filling in the symbols ⊂ or ⊄ in the blank spaces : { x : x is a student of Class XI of your school}. . .{ x : x student of your school}

Let R be the set of points inside a rectangle of sides a and b with two sides along the positive directions of x-axis and y-axis . Then :

From the pair of linear equations in the following and problems, and find their solutions graphically. 10 students, of Class X took part in a Mathematics quiz. If the number of girs is 4 more than the number of boys, find the number of boys and girls who took part in the quiz.

Let S be the set of the first 21 natural numbers, then the probability of Choosing {x,y,z}subeS , such that x,y,z are not consecutive is,