Three coins are tossed once. Find the probability of getting at most two tails.

$A, B, C, D$ cut a pack of $52$ well-shuffled playing cards successively in the same order. If the person who cuts a spade first wins the game and the game continues until this happens,then the probability that $A$ wins the game is

Two dice are thrown simultaneously. The probability of getting two numbers whose product is even is

In a college,$40 \%$ of students attend the Mathematics class,$30 \%$ of students attend the Physics class,and $20 \%$ of students attend both classes. If a student is chosen at random from the college,what is the probability that the chosen student attends only one class?

Two numbers $a$ and $b$ are chosen at random from the set of first $30$ natural numbers. Then the probability that $a^2 - b^2$ is divisible by $3$ is (in $/87$)

The probability of getting head and tail alternately in three throws of a coin (or a throw of three coins) is: