Four coins are tossed. The probability that at least one head turns up, is
$1/16$
$1/4$
$15/16$
None of these
A die is thrown, find the probability of following events: A number less than or equal to one will appear,
A determinant is chosen at random. The set of all determinants of order $2$ with elements $0$ or $1$ only. The probability that value of the determinant chosen is positive, is
A coin is tossed $3$ times by $2$ persons. What is the probability that both get equal number of heads
On her vacations Veena visits four cities $(A,\,B ,\, C$ and $D$ ) in a random order. What is the probability that she visits $A$ before $B$ and $B$ before $C ?$
The probabilities of a student getting $I, II$ and $III$ division in an examination are respectively $\frac{1}{{10}},\,\frac{3}{5}$ and $\frac{1}{4}.$ The probability that the student fails in the examination is