Test Index

Probability

Question : 108 of 127

Marks: +1, -0

Solution:

Concept:

Probability of an event =

\frac{\text{favorable outcomes}}{\text{total outcomes}}

. Use complement to find "neither".

Explanation:

Total outcomes when two dice are thrown =

6 \times 6 = 36

Outcomes with sum 7:

(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)

→

6

outcomes.

Outcomes with sum 11:

(5,6), (6,5)

→

2

outcomes.

Total outcomes with sum 7 or 11 =

6 + 2 = 8

Probability of sum 7 or 11 =

\frac{8}{36} = \frac{2}{9}

Probability of neither 7 nor 11 =

1 - \frac{2}{9} = \frac{7}{9}

Answer:

\frac{7}{9}

Go to Question:

Prev Question

Next Question