ProbabilityHardBloom L3
Question
Starting at $(0,0)$ an object moves in coordinate plane by a sequence of steps, each of length one. Each step is left, right up or down, all four equally likely. Find the probability that the object reaches $(2,2)$ in six or fewer steps.
Options
A.$\frac{3}{64}$
B.$\frac{1}{64}$
C.$\frac{5}{64}$
D.$\frac{5}{32}$
Solution
Sol. [Key Concept: Object moving by unit steps: count favorable lattice routes.]
4 steps or 6 steps
$$P = \frac{\frac{4!}{2!2!}}{4^{4}} + \frac{+ 2\left( \frac{6!}{312!1!} - \frac{4!}{2!2!} \times 2! \right)}{4^{6}} = \frac{3}{64}$$
Create a free account to view solution
View Solution FreeMore Probability Questions
A pair of dice is thrown. If the two numbers appearing on them are different, the probability that the sum is 6, is-...For two given events A and B, P(A ∩ B) is...If ' $n$ ' different things are distributed among $x$ boys and $y$ girls. Find the probability that the number of things...A number is chosen at random from the numbers 10 to 99. By seeing the number a man will laugh if product of digits is 12...The number ′a′ is randomly selected from the set {0, 1, 2, 3, ........ 98, 99}. The number ′b′ i...