# Easy Probability Solved QuestionAptitude Discussion

 Q. Set A = {2,3,4,5} Set B = {4,5,6,7,8} Two integers will be randomly selected from the sets above, one integer from Set $A$ and one integer from Set $B$. What is the probability that the sum of the two integers will equal 9?
 ✔ A. 0.2 ✖ B. 0.25 ✖ C. 0.3 ✖ D. 0.33

Solution:
Option(A) is correct

There are four ways of selectiing an integer from Set A = {2,3,4,5} AND there are 5 ways of selecting an integer from Set B = {4,5,6,7,8}.

So sample space,

$n(S)=4\times 5=20$

Now, favourable cases: {2, 7}, {3,6}, {4, 5}, {5, 4} i.e. 4 cases.

$n(E)=4$

$\therefore \text{Probability}= \dfrac{\text{Favorable Cases}}{\text{Total Cases}}$

$P(E)=\dfrac{n(E)}{n(S)}$

$=\dfrac{4}{20}$

$=\textbf{0.20}$