A student has 6 nickel 14 dimes and 8 quarter. What is the ratio of dimes to quarter ?

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

you pay 3.3 cents per minute for long-distance phone calls on your phone. your phone bill is $3.40 write and solve an equation t

MaRussiya [10]

If you would like to know the number of minutes of long-distance calls you made, you can calculate this using the following steps:

3.3 cents = $0.033
m = $3.40 / 3.3 cents
m = $3.40 / $0.033 = 3.40 / 0.033
m = 103.03 minutes

The correct result would be <span>103.03 minutes.</span>

5 0

3 years ago

AJ is the bisector of ∠HJI. Determine the value of x.

atroni [7]

Answer:

C

Step-by-step explanation:

If x was equal to 12, 22.5 or 10 the side would be too large compared to 15. This is only correct if the drawing is to scale, however.

8 0

2 years ago

If Jeff washes his car in 6 minutes and bob washes the same car in 8 minutes. How long does it take both of them to wash the sam

Tatiana [17]

Answer:

3 3/7 or 24/7 mins

Step-by-step explanation:

Let total job = X

Jeff's rate = X/6

Bob's rate = X/8

Combined rate = X/6 + X/8

(4X × 3X)/24 = 7X/24

7X/24 = X/T

T = X ÷ (7X/24)

T = X × (24/7X)

T = 24/7 mins

Shortcut:

T = product of individual times/sum of individual times

T = (6×8)/(6+8)

T = 48/14

T = 24/7

T = 3 3/7 mins

8 0

2 years ago

Read 2 more answers

Plz Help:)

Svetlanka [38]

I think it’s D, hope that helps

8 0

3 years ago