Explain this probability question and tell us how it is being answered
here using formula.
Rd Sharma Class 10th Cbse, PROBABILITY.
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Solution:
Given: A dice is thrown once.
Required to find:
(i) Probability of getting a prime number.
(ii) Probability of getting 2 or 4.
(iii) Probability of getting a multiple of 2 or 3.
(iv) Probability of getting an even number.
(v) Probability of getting a number greater than five.
(vi) Probability of lying between 2 and 6.
The total number on a dice is 6, i.e., 1, 2, 3, 4, 5 and 6.
(i) Prime numbers on dice are 2, 3, and 5. So, the total number of prime numbers is 3.
We know that, Probability = Number of favourable outcomes/ Total number of outcomes
Thus, the probability of getting a prime number = 3/6 = 1/2
(ii) For getting 2 and 4, clearly, the number of favourable outcomes is 2.
We know that Probability = Number of favourable outcomes/ Total number of outcomes
Thus, the probability of getting 2 or 4 = 2/6 = 1/3
(iii) Multiple of 2 are 3 are 2, 3, 4 and 6.
So, the number of favourable outcomes is 4.
We know that, Probability = Number of favourable outcomes/ Total number of outcomes
Thus, the probability of getting a multiple of 2 or 3 = 4/6 = 2/3
(iv) An even prime number is 2 only.
So, the number of favourable outcomes is 1.
We know that, Probability = Number of favourable outcomes/ Total number of outcomes
Thus, the probability of getting an even prime number = 1/6
(v) A number greater than 5 is 6 only.
So, the number of favourable outcomes is 1.
We know that, Probability = Number of favourable outcomes/ Total number of outcomes
Thus, the probability of getting a number greater than 5 = 1/6
(vi) Total number on a dice is 6.
Numbers lying between 2 and 6 are 3, 4 and 5
So, the total number of numbers lying between 2 and 6 is 3.
We know that, Probability = Number of favourable outcomes/ Total number of outcomes
Thus, the probability of getting a number lying between 2 and 6 = 3/6 =1/2