Subject
Quantitative Aptitude
Topic
Permutation & Combination
In a group of 6 boys and 4 girls, four children are to be selected. In how many different ways can they be selected such that at least one boy should be there?
In a group of 6 boys and 4 girls, four children are to be selected. In how many different ways can they be selected such that at least one boy should be there?
ক)
159খ)
194গ)
205ঘ)
209Explanation
We may have (1 boy and 3 girls) or (2 boys and 2 girls) or (3 boys and 1 girl) or (4 boys). Required number of ways = (6C1 x 4C3) + (6C2 x 4C2) + (6C3 x 4C1) + (6C4) = (6C1 x 4C1) + (6C2 x 4C2) + (6C3 x 4C1) + (6C2) = (6 x 4) + {(6 x 5)/( 2 x 1) x (4 x 3)/( 2 x 1)} + [{(6 x 5 x 4)/(3 x 2 x 1)}x 4] + (6 x 5)/( 2 x 1) = (24 + 90 + 80 + 15) = 209.Related questions
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