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the number of all three elements subsets of the se
Question:
The number of all three elements subsets of the set
$\{a_1, a_2, a_3 . . . a_n\}$
which contain
$a_3$
is
BITSAT - 2014
BITSAT
Updated On:
Jan 30, 2025
$^nC_3$
$^{n - 1} C_3$
$^{n - 1} C_2$
None of these
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The Correct Option is
C
Solution and Explanation
The number of three elements subsets containing
$a^3$
is equal to the number of ways of selecting
$2$
elements out of
$n - 1$
elements. So, the required number of subsets is
$^{n -1}C_2$
.
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