Question

A bag contains 15 marbles numbered from 1 to 15. Two marbles are selected from the bag at the same time. Let event E = the two numbers do NOT differ by 10 How many outcomes are in the complement of E?

Answer 1

5 outcomes will give us the complement of E

Explanation:

We have given the numbers from 1 to 15

E is the event where two number do not differ by 10

Complement of the event means NOT of the event.

Favourable outcomes that is will give the difference of 10 will be

(15,5), (14,4) , (13,3) , (12,2) ,(11,1)

Hence, total number of favourable outcomes are 5

Answer 2

When we say, complement of event E, where E is such that the numbers will not have a difference of 10, we mean to determine the number of outcomes in which the numbers randomly picked will have a difference of 10. These pairs are 15 and 5, 14 and 4, 13 and 3, 12 and 2, 11 and 1. Thus, there are 5 complements of E.