The number of ways in which any four letters can be selected from the word ‘$CORGOO$’ is
$15$
$11$
$7$
None of these
The number of words not starting and ending with vowels formed, using all the letters of the word $'UNIVERSITY'$ such that all vowels are in alphabetical order, is
In how many ways a team of $11$ players can be formed out of $25$ players, if $6$ out of them are always to be included and $5$ are always to be excluded
There are $15$ persons in a party and each person shake hand with another, then total number of hand shakes is
The value of $\sum\limits_{r = 1}^{15} {{r^2}\,\left( {\frac{{^{15}{C_r}}}{{^{15}{C_{r - 1}}}}} \right)} $ is equal to
The number of ways to give away $25$ apples to $4$ boys, each boy receiving at least $4$ apples, are