10th Class Mathematics Probability Question Bank MCQs - Probability

A bag contains 4 red, 5 black and 3 yellow balls. A ball is taken out of the bag at random. Find the probability that the ball taken out is not of red colour.

A) 1

B) 4

C) 5

D) 25

Correct Answer: D

Solution :

[d] If two unbiased coins are tossed simultaneously we obtained possible outcomes.

\[HH,HT,TH,TT\]

Hence. Total number of outcomes = 4

No head is obtained if the event TT occurs.

Hence, number of favourite outcomes = 1

Hence. Required probability \[=\frac{1}{4}\]

But, given probability \[=\frac{A}{B}\]

So,\[A=1\]

and \[B=4\]

Therefore, \[{{(A+B)}^{2}}={{(1+4)}^{2}}={{(5)}^{2}}=25\]