Question

Let ξ = the set of all triangles , P = the set of all isosceles triangles, Q = the set of all equilateral triangles, R = the set of all right angled triangles. What do the sets P ∩ Q and R – P represent respectively?

(a) The set of isosceles triangles; the set of non-isosceles right angled triangles.

(b) The set of isosceles triangles; the set of right angled triangles.

(c) The set of equilateral triangles; the set of right angled triangles.

(b) The set of isosceles triangles; the set of equilateral triangles.

Answer 1

Correct option is (c) The set of equilateral triangles; the set of right angled triangles.

ξ = the set of all triangles

P = the set of all isosceles triangle

Q = the set of all equilateral triangle

R = the set of all right angled triangle

P ∩ Q = the set of all equilateral triangles are isosceles but all isosceles triangle are not equilateral.

R − P = Set of all right angled triangle which are not isosceles (because all right angled triangle are not isosceles triangle.)