A frog moves in a sequence of unit steps. Each step is N, S, E or W with equal probability. It starts at the origin. Find the probability that it reaches (2, 2) in less than 7 steps.

Respuesta :

The answer is 067.

It takes an even number of steps for the object to reach (2,2), so the number of steps the object may have taken is either 4 or 6 .

If the object took 4 steps, then it must have gone two steps [tex]$\mathrm{N}$[/tex] and two steps E, in some permutation. There are [tex]$\frac{4 !}{2 ! 2 !}=6$[/tex] ways for these four steps of occuring, and the probability is [tex]$\frac{6}{4^{4}}$[/tex].

If the object took 6 steps, then it must have gone two steps N and two steps E, and an additional pair of moves that would cancel out, either N / S or W/E. The sequences N, N, N, E, E, S can be permuted in [tex]$\frac{6 !}{3 ! 2 ! 1 !}=60$[/tex] ways. However, if the first four steps of the sequence are N, N, E, E in some permutation, it would have already reached the point (2,2) in four moves. There are [tex]$\frac{4 !}{2 ! 2 !}$[/tex] ways to order those four steps and [tex]$2 !$[/tex] ways to determine the order of the remaining two steps, for a total of 12 sequences that we have to exclude. This gives [tex]$60-12=48$[/tex] sequences of steps. There are the same number of sequences for the steps N, N, E, E, E, W, so the probability here is [tex]$\frac{2 \times 48}{4^{6}}$[/tex].

The total probability is [tex]$\frac{6}{4^{4}}+\frac{96}{4^{6}}=\frac{3}{64}$[/tex], and [tex]$m+n=067$[/tex].

What is probability?

  • Probability is synonymous with possibility. It is a mathematical discipline that deals with the occurrence of a random event. The value ranges from zero to one.
  • Probability has been introduced in mathematics to predict the likelihood of occurrences occurring. Probability is defined as the degree to which something is likely to occur.
  • This is the fundamental probability theory, which is also utilized in probability distribution, in which you will learn about the possible results of a random experiment.
  • To determine the likelihood of a particular event occurring, we must first determine the total number of alternative possibilities.

To learn more about probability visit:

https://brainly.com/question/11234923

#SPJ4