NCERT Solutions
Class 10 - Mathematics - Chapter 14: PROBABILITY - Exercise 14.1
Question 22

Question. 22

Refer to Example 13.

(i) Complete the following table:

Event:
‘Sum on 2 dice’
23456789101112
Probability\(\frac{1}{36}\)\(\frac{5}{36}\)\(\frac{1}{36}\)

(ii) A student argues that there are 11 possible outcomes 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12. Therefore, each of them has a probability 1/11. Do you agree with this argument? Justify your answer.

Answer:

(i) Probabilities of sums 2 to 12 respectively are: \(\dfrac{1}{36}\), \(\dfrac{2}{36}\), \(\dfrac{3}{36}\), \(\dfrac{4}{36}\), \(\dfrac{5}{36}\), \(\dfrac{6}{36}\), \(\dfrac{5}{36}\), \(\dfrac{4}{36}\), \(\dfrac{3}{36}\), \(\dfrac{2}{36}\), \(\dfrac{1}{36}\).

(ii) No. The sums are not equally likely; for example, 7 can occur in 6 different ways, while 2 or 12 can occur in only 1 way each, so their probabilities are not all 1/11.

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