If a fair coin is tossed twice and $X$ = number of heads, then $P[X = 1]$ equals:
A$1/4$
B$3/4$
C$2/3$
D$1/2$
Answer & Solution
Correct answer: D. $1/2$
$X = 1$ corresponds to events {HT, TH}, so $P[X=1] = 2/4 = 1/2$.
Related questions
Two coins tossed. P(both heads) =Bag has 4 red, 6 blue. P(red) =Probability of rolling 6 on a die:Probability of heads on a fair coin is:If a fair six-sided die is rolled twice, the probability that the sum is divisible by 3 isA bag has 3 red and 2 black balls. Probability of red ball drawn at random:Probability of getting an even number on rolling a single die:Probability of drawing a king from a standard deck of 52 cards: