CBSE Previous Year Question Paper
Class 10 Maths | 2018 Section B Question 11

An easy 2 mark question that appeared in 2018 CBSE board paper. Answering the question requires basic understanding of the number of outcomes possible when two dice are tossed together and knowing the meaning of what it means to get a doublet.

Question 11: Two different dice are tossed together, Find the probability:
(i)   of getting a doublet
(ii) of getting a sum 10, of the numbers on the two dice

Video Explanation

Explanatory Answer

Step 1: Find the denominator. Compute the total number of outcomes when two dice are tossed

Total number of outcomes when 2 different dice are tossed together = 6 × 6 = 36

Part (i) Step 2: Find the numerator. Compute the number of ways getting a doublet

What is a doublet?
Getting numbers of the form (1, 1) (2, 2) (3, 3) (4, 4) (5, 5) (6, 6) when two dice are tossed is called a doublet.

How many doublets exist when two dice are tossed together?
A total of 6 doublets exist when two dice are tossed together.

Part (i) Step 3: Find the probability of the event

∴ Probability of getting a doublet = \\frac{\text{Number of outcomes of getting a doublet}}{\text{Total number of outcomes}}) = \\frac{6}{36}) = \\frac{1}{6})

Part (ii) Step 2: Find the numerator. Compute the number of ways getting a sum of 10 when two dice are tossed together.

The outcomes that result in a sum of 10 are (4, 6), (5, 5), and (6,4).
i.e., a total of 3 outcomes.

Part (ii) Step 3: Find the probability of the event

∴ Probability of getting a sum of 10 = \\frac{\text{Number of outcomes in which sum is 10}}{\text{Total number of outcomes}}) = \\frac{3}{36}) = \\frac{1}{12})