Question

Describe the diagram

Answer 1

The diagram represents 3 sets assuming they refer to 3 activities A, B and C.

The shaded point on A shows those engage in activities A only.

The shaded point on B shows those engage in activities B only.

The shaded point on C shows those engage in activities C only.

Incidentally the numbers of people engage in activities A only and B only are the same number.

The colour grade for the following is the same with that engage in only activity B;

The intersection of A and B

The intersection of B and C

The intersection of A and C

Therefore it means the numerical value is the same with that of B only;

A n B= B n C = A n C = n( B only); n on the right represent intersection and on the left number.

A n B n C = no of people engaged in all 3 activities.

A n B n C = n( A only) = n( B only) ;

From the colour grade

Note: n on the right represent intersection and on the left

Answer 2

The diagram reprents the 3 sets and the universal set . The shaded portion clearly can be seen as :

`A \cap B \cap C + A - (A \cap B) - (A \cap C) + A \cap B \cap C + C - (C \cap B) - ( C \cap A) + (A \cap B \cap C)`

Shaded region =
`3(A \cap B \cap C) + A + C - (A \cap B) - 2(A \cap C) - (C \cap B)`

Try to understand some what complex