NTSE Stage 2 SAT 2016 Question Paper

Question : 60 of 100

Marks: +1, -0

Three dice are thrown simultaneously. The probability of getting a total of at least 5 of the numbers appearing on their tops is :

$5/54$
$7/54$
$49/54$
$53/54$

Validate

Solution:

P(sum at least 5) = 1–P(Getting sum 3 or 4)
no of ways getting sum 3 = 1 way i.e. (1, 1, 1)
no of ways getting sum 4 = 3 ways i.e
(1, 1, 2),(1, 2, 1), (2, 1, 1)
So P(sum at least 5)=

1-{1+3}/216=212/216=53/54

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