Question

A bag contains 20 discs, which Are numbered from 1 to 20. If one disc is drawn at random from the bag, find the probability that it bears : 

i) an even number, 

ii) Prime number, 

iii) Multiple of 5, 

iv) Two digit odd number.

Answer 1

Total number of possible outcomes = 20 

i) For probability of the disc bears an even number 

No. of favourable outcomes = 10 

Probability

ii) For probability of the disc bears a prime number 

No. of favourable outcomes = 8 

Probability = \(\frac{8}{20}=\frac{2}{5}\)

iii) For probability of the disc bears a multiple of 5 

No. of favourable outcomes = 4 

Probability = \(\frac{4}{20}=\frac{1}{5}\)

iv) For probability of the disc bears a two digit odd number 

No. of favourable outcomes = 5 

Probability = \(\frac{5}{20}=\frac{1}{4}\)