Which one is correct

The speed with which utility companies can resolve problems is very important. GTC, the Georgetown Telephone Company, reports it

brilliants [131]

Answer:

(a) 11.25 and 1.68

(b) 0.1651

(c) 0.3903

(d) 0.6865

Step-by-step explanation:

We are given that GTC, the Georgetown Telephone Company, reports it can resolve customer problems the same day they are reported in 75% of the cases and suppose the 15 cases reported today are representative of all complaints.

This situation can be represented through Binomial distribution as;

$P(X=r)= \binom{n}{r}p^{r}(1-p)^{n-r} ; x = 0,1,2,3,....$

where, n = number of trials (samples) taken = 15

r = number of success

p = probability of success which in our question is % of cases in

which customer problems are resolved on the same day, i.e.;75%

So, here X ~ $Binom(n=15,p=0.75)$

(a) Expected number of problems to be resolved today = E(X)

E(X) = $\mu$ = n * p = 15 * 0.75 = 11.25

Standard deviation = $\sigma$ = $\sqrt{n*p*(1-p)}$ = $\sqrt{15*0.75*(1-0.75)}$ = 1.68

(b) Probability that 10 of the problems can be resolved today = P(X = 10)

P(X = 10) = $\binom{15}{10}0.75^{10}(1-0.75)^{15-10}$

= $3003*0.75^{10} *0.25^{5}$ = 0.1651

(c) Probability that 10 or 11 of the problems can be resolved today is given by = P(X = 10) + P(X = 11)

= $\binom{15}{10}0.75^{10}(1-0.75)^{15-10}+\binom{15}{11}0.75^{11}(1-0.75)^{15-11}$

= $3003*0.75^{10} *0.25^{5} + 1365*0.75^{11} *0.25^{4}$ = 0.3903

(d) Probability that more than 10 of the problems can be resolved today is

given by = P(X > 10)

P(X > 10) = P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) + P(X = 15)

= $\binom{15}{11}0.75^{11}(1-0.75)^{15-11}+\binom{15}{12}0.75^{12}(1-0.75)^{15-12} + \binom{15}{13}0.75^{13}(1-0.75)^{15-13}+\binom{15}{14}0.75^{14}(1-0.75)^{15-14} + \binom{15}{15}0.75^{15}(1-0.75)^{15-15}$

= $1365*0.75^{11} *0.25^{4} + 455*0.75^{12} *0.25^{3}+105*0.75^{13} *0.25^{2} + 15*0.75^{14} *0.25^{1}+1*0.75^{15} *0.25^{0}$

= 0.6865

3 0

3 years ago

Please help a girl out

xxMikexx [17]

Answer:

Quadratic formula is in the 2nd picture.

Step-by-step explanation:

Answers in the photo.

Solve the equation for r by finding a,b, and c of the quadratic then applying the quadratic formula.

3 0

3 years ago

Read 2 more answers

PLEASE HELP ASAP 35 POINTS

podryga [215]

Your answer is A

It cannot be C because the line y > -2 uses the (>) greater than symbol.

When equations have a greater than symbol, they are graphed using a dotted line.

It cannot be D because the line is y ≤ - l x-1 l

with the less than or equal to sign (≤) , you use a solid line to graph

With the greater than symbol for y > -2 , the shaded region must be above this line.

With the less than or equal to sign in y ≤ - l x-1 l , the shaded region must be below the line.

Hope I helped - message me if you have any questions :)

5 0

3 years ago

the spice recipe calls for 1/2 tsp of crushed red pepper for every 1 1/4 tsp of black pepper. you use 6 tsp of crushed red peppe

aksik [14]

15 tsp of black pepper was used. 2 half tsp = one whole tsp. 12 half tsp is equivalent to 6 tsp. Multiply 1 1/4 by 12 and you get 15.

4 0

3 years ago

Two lines, C and D, are represented by the equations given below:

lakkis [162]

y=x+14 line 1

y=3x+2 line 2

These are both the equation of lines written in slope intercept form

y=mx+b where m is the slope and the point (0,b) is the y intercept.

The first line has a slope of m=1. The 2nd line has a slope of m=3

Since these lines have different slopes, they are not parallel, thus they will cross at some point. What you have to determine is where the lines cross, which will be a point (x,y) that is on both lines.

We already have y solved in terms of x from either equation so we can use substitution to solve the system.

Since y=x+14 from line 1, put x+14 in place of y in the equation of line 2.

x+14=3x+2

solve for x.

Subtract x from both sides...

14= 3x-x+2

14=2x+2

subtract 2 from both sides

14-2=2x

12=2x

divide both sides by 2

6=x

We now have the x value of the common point. Plug the value 6 in for x in one of the original equations and solve for y.

y=6+14

y=20

These two lines cross at the point (6,20) which is a point the two lines have in common.

Hope I helped (SharkieOwO)

3 0

3 years ago