probability, Mathematics

Assignment Help:
Question: There are 6 letters and 6 self addressed envelopes.What is the probability that atleast 1 is placed correctly??

Ans: If we let A be the event that letter A is in the correct envelope, and
similarly B is event that letter B is in the correct envelope, then

P(A) = 1/5

P(A and B) = 1/5 x 1/4

Now use the inclusion, exclusion formula to get the probability that A or
B or C .... or E are correctly placed.

P(A or B or C .... or E) = P(A) + P(B) + P(C) + P(D) + P(E)
- P(A and B) - P(B and C) -....
+ P(A and B and C) + P(B and C and D) + ....
- P(A and B and C and D) - P(...) -......
+ P(A and B and C and D and E)

= 5 x (1/5)
- 5C2 x (1/5)(1/4)
+ 5C3 x (1/5)(1/4)(1/3)
- 5C4 x (1/5)(1/4)(1/3)(1/2)
+ (1/5)(1/4)(1/3)(1/2)(1/1)

5x4 1 5x4x3 1 5x4x3x2 1 1
1 - ---- x ---- + ------ x ----- - --------- x ------- + --------
1x2 5x4 1x2x3 5x4x3 1x2x3x4 5x4x3x2 5x4x3x2x1

= 1 - 1/2! + 1/3! - 1/4! + 1/5!


This is the probability that at least one letter is correctly placed.

Related Discussions:- probability

One integer is four times other what is the value of lesser, One integer is...

One integer is four times other. The sum of the integers is 5. What is the value of the lesser integer? Let x = the lesser integer and now let y = the greater integer. The ?rst

Ratio math help, Mr.Tanaka has 56 students in his choir the ratio of boys ...

Mr.Tanaka has 56 students in his choir the ratio of boys to girls is 3:4 how many boys and girls are in his class

Determine the height of the washington monument, Determine the height of th...

Determine the height of the Washington Monument to the nearest tenth of a meter. a. 157.8 m b. 169.3 m c. 170.1 m d. 192.2 m c. The height of the monument is the add

Quantitative method, Year 1 2 3 4 ...

Year 1 2 3 4 5 6 7 8 9 10 Corn revenue 40 44 46

Estimate the cost of the car, Kyra receives a 5% commission on every car sh...

Kyra receives a 5% commission on every car she sells. She received a $1,325 commission on the last car she sold. What was the cost of the car? Use the proportion part/whole =

Fact - undetermined coefficients, Here, let's take a look at sums of the fu...

Here, let's take a look at sums of the fundamental components and/or products of the fundamental components. To do this we'll require the following fact. Fact- Undetermined Co

Basic mathematics, I need help with my homework, I am to the edge right now...

I need help with my homework, I am to the edge right now with this w=5pq/2

Rounding, how do you round to the nearest dollars?

how do you round to the nearest dollars?

Illustration of integration by parts - integration technique, Example of In...

Example of Integration by Parts - Integration techniques Some problems could need us to do integration by parts many times and there is a short hand technique that will permit

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd