$^n{C_r}\,{ \div ^n}{C_{r - 1}} = $
$\frac{{n - r}}{r}$
$\frac{{n + r - 1}}{r}$
$\frac{{n - r + 1}}{r}$
$\frac{{n - r - 1}}{r}$
(c) On simplifying you will get $\frac{{n – r + 1}}{r}$.
The total number of three-digit numbers, with one digit repeated exactly two times, is
$^n{C_r}{ + ^{n – 1}}{C_r} + ……{ + ^r}{C_r}$ =
There are two urns. Urm $A$ has $3$ distinct red balls and urn $B$ has $9$ distinct blue balls. From each urm two balls are taken out at random and then transferred to the other. The number of ways in which this can be done is
In a club election the number of contestants is one more than the number of maximum candidates for which a voter can vote. If the total number of ways in which a voter can vote be $62,$ then the number of candidates is :-
The number of $4-$letter words, with or without meaning, each consisting of $2$ vowels and $2$ consonants, which can be formed from the letters of the word $UNIVERSE$ without repetition is $………$.
Confusing about what to choose? Our team will schedule a demo shortly.
