Data Analysis Practice Test 1

ORIGINAL QUESTIONS FROM PREVIOUS YEAR PAPERS

Directions (49-51): Study the following information carefully to answer these questions:
A box contains 4 red pens, 9 blue pens and 5 green pens. The pens are to be drawn randomly as per the specifications given in each of the following questions:

Question : 49 of 65

Marks: +1, -0

If three pens are to be randomly drawn from the box, what will be the probability that all of them are blue?

$3 / 68$
$7 / 68$
$3/ 34$
$7 / 34$
None of these

Validate

Solution:

Probability of three blue pens are to be randomly drawn from the box is:

^9C_3/{^18C_3}=9!/{3!6!}×{15!3!}/18!

={9×8×7×6!}/{3×2×1×6!}

×{15!×3×2×1}/{18×17×16×15!}

=84/816=7/68

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