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Numerical Ability
Permutation and Combination
There are 4 boxes colored red, yellow, green and blue. If 2 boxes are selected, how many combinations are there for at least one green box or one red box to be selected?
Read Solution (Total 4)
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- ans is 5
4C2-1=5
- 9 years agoHelpfull: Yes(8) No(1)
- 3*3-1=5
3 bcz 3 com pf at least 1 g bal
and 3 bcz 3 com pf at least 1 r bal
-1 bz one combn havg both g r ball - 9 years agoHelpfull: Yes(0) No(5)
- answer=5
4c2-1=5 - 9 years agoHelpfull: Yes(0) No(0)
- given 4 boxes of 4 different colors and we have to choose two boxes out of these.
so total number of combinations =4C2=6
Combinations are - GB,GR,GY,BR,BY,RY
So the combinations of at least 1 green ball =3
the combination of at least 1 red ball =3
total combinations =3+3–1=5 ( 1 combination deducted because GR was included in both sets of combination)
so therefore there are 5 combinations for selecting at least 1 red ball or 1 green ball. - 1 year agoHelpfull: Yes(0) No(0)
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