10th Class Mathematics Probability Question Bank MCQs - Probability

A number is selected from first 50 natural numbers. What is the probabilite that it is a multiple of 4 or 5?

A) \[\frac{9}{25}\]

B) \[\frac{2}{5}\]

C) \[\frac{6}{25}\]

D) \[\frac{23}{50}\]

Correct Answer: B

Solution :

[b] Total number of possible outcomes = 50

Let E be the event 'selecting a multiple of 4 aor 5'.

So, the favourable outcomes are

\[\{4,8,12,16,20,24,28,32,36,40,44,48,5,10,15,25,30,\] \[35,45,50\}\]i.e., 20 in number.

\[\therefore \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,P(E)=\frac{20}{50}=\frac{2}{5}\]