If $4$ boys and $3$ girls are standing in a row for an interview,what is the probability that they stand in alternating positions?

Five horses are in a race. $Mr. A$ selects two of the horses at random and bets on them. The probability that $Mr. A$ selected the winning horse is

All the spades are taken out from a pack of cards. From these cards,cards are drawn one by one without replacement until the ace of spades comes. The probability that the ace of spades comes in the $4^{th}$ draw is

$A$ five-digit number is formed using the digits $1, 2, 3, 4, 5$ without repetition. What is the probability that the number is divisible by $4$?

The probability that three cards drawn from a pack of $52$ cards are all red is

$A$ bag contains $5$ white, $7$ red, and $8$ black balls. If four balls are drawn one by one without replacement, what is the probability that all are white?