1 1 vote In a box, there are $4$ coins. One coin is biased with probability of head $0.8$, and the other $3$ coins are fair coins with probability of head $0.5$. If one coin is chosen at random, what is the probability of getting a head?$0.525$ $0.575$ $0.625$ $0.675$ IIITH-PGEE iiith-pgee2026-cs-memorybased goclasses engineering-mathematics probability one-mark + – GO Classes 123 views answer comment Share Follow Print 0 reply Please log in or register to add a comment.
0 0 votes Given:\begin{align*}P(F) &= \frac{3}{4}, \quad P(\text{Heads} \mid \text{Fair}) = 0.5 \\P(B) &= \frac{1}{4}, \quad P(\text{Heads} \mid \text{Biased}) = 0.8\end{align*}By the Total Probability Theorem:\begin{align*}P(\text{Heads}) &= P(\text{Heads} \mid \text{Fair}) \times P(F) + P(\text{Heads} \mid \text{Biased}) \times P(B) \\ &= 0.5 \times \frac{3}{4} + 0.8 \times \frac{1}{4} \\ &= \frac{1.5}{4} + \frac{0.8}{4} \\ &= \frac{2.3}{4} \\ &= \boxed{0.575}\end{align*} Avanish_Grampurohit answered May 12 • edited May 12 by Avanish_Grampurohit Avanish_Grampurohit comment Share Follow 0 reply Please log in or register to add a comment.