If the letters of the word $SUCCESS$ are rearranged,what is the probability that all identical letters come together (in $/35$)?

$3$ balls are drawn one after the other without replacement from an urn containing $4$ red,$5$ blue and $6$ yellow balls. The probability of getting three different coloured balls is

From a month of $31$ days,$3$ different dates are selected at random. If the probability that these dates are in an increasing $A$.$P$. is equal to $\frac{a}{b}$,where $a, b \in N$ and $\text{gcd}(a, b) = 1$,then $a + b$ is equal to ————

$A$ bag contains $6$ white and $4$ black balls. $A$ die is rolled once and the number of balls equal to the number obtained on the die are drawn from the bag at random. The probability that all the balls drawn are white is:

If two sections of strengths $30$ and $45$ are formed from $75$ students who are admitted in a school,then the probability that two particular students are always together in the same section is

In a consignment of $15$ articles,it is found that $3$ are defective. If a sample of $5$ articles is chosen at random from it,then the probability of having $2$ defective articles is