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India
Class XI

Introduction to Combinations

Interactive practice questions

Ben has $3$3 shirts: crimson ($C$C), pink ($P$P) and white ($W$W), and $4$4 ties: blue ($B$B), grey ($G$G), red ($R$R) and yellow ($Y$Y).

a

Fill in the array using capital letters to show all the possible outfits Ben could wear.

  Crimson ($C$C) Pink ($P$P) White ($W$W)
Blue ($B$B) $C$C,$\editable{}$ $\editable{}$,$B$B $\editable{}$,$B$B
Grey ($G$G) $C$C,$\editable{}$ $\editable{}$,$G$G $W$W,$\editable{}$
Red ($R$R) $\editable{}$,$R$R $\editable{}$,$R$R $W$W,$\editable{}$
Yellow (Y) $\editable{}$,$Y$Y $P$P,$\editable{}$ $\editable{}$,$Y$Y
b

How many different outfits are possible?

Easy
1min

Evaluate $\nCr{7}{2}$7C2.

Easy
< 1min

Find the value of $\binom{7}{3}$(73).

Easy
1min

Find the value of $\binom{10}{9}$(109).

Easy
< 1min
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Outcomes

11.A.PC.1

Fundamental principle of counting. Factorial n. Permutations and combinations, derivation of formulae and their connections, simple applications.

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