1.

probability that the bomb will hit the target is 0.8 find the probability that out of ten bombs dropped ,excetly two will miss the target

Answer»

\large\underline{\sf{Solution-}}

We know,

By Binomial Distribution,

\boxed{ \bf \: P(r) = \:^n C_r {p}^{r}  {q}^{n - r} }

where,

  • n = number of trials

  • q = probability of failure

  • r = random variable whom success is desired.

and

  • p + q = 1.

Let's SOLVE the problem now!!

Here, given that

  • Number of bombs dropped, n = 10.

  • Probability that BOMB hit the target, p = 0.8

So,

  • Probability that bimb will not hit target, q = 1 - 0.8 = 0.2

Now,

We have to find the probability exactly 2 bombs will miss the target.

\bf :\longmapsto\:P(exactly \: 2 \: bombs \: miss \: the \: target)

\:  \:  \bf \:  =  \: P(exactly \: 8 \: bombs \: hit \: the \: target)

\:  \:  =  \sf \: \:^{10} C_8 \:   \times {(0.8)}^{8}  \times  {(0.2)}^{2}

\:  \:  =  \sf \: \dfrac{10  \times 9}{2 \times 1}  \times  {\bigg( \dfrac{8}{10} \bigg) }^{8}  \times  {\bigg( \dfrac{2}{10} \bigg) }^{2}

\:  \:  =  \sf \: 45 \times  {\bigg(\dfrac{4}{5}  \bigg) }^{8}  \times  {\bigg( \dfrac{1}{5} \bigg) }^{2}

\:  \:  =  \sf \: 45 \times \dfrac{ {4}^{8} }{ {5}^{8} }  \times \dfrac{1}{ {5}^{2} }

\:  \:  =  \sf \: \dfrac{9 \times  {2}^{16} }{ {5}^{9} }

Additional Information :-

If the following conditions are satisfied, then X has a binomial distribution with parameters n and p, represented as B(n,p).

  • 1. The number of observations n is fixed.

  • 2. Each observation is independent.

  • 3. Each observation represents ONE of two outcomes (succes, p or failure, q).

  • 4. The probability of "success" p is the same for each OUTCOME.



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