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3 years ago

Five bulbs of which three are defective are to be tried in two bulb points in a dark room

Mathematics

1 answer:

iogann1982 [59]3 years ago

8 0

Answer:

D 7

Step-by-step explanation:

Total no. of bulb= 5

no. of defected bulb= 3

no. of not defected bulb=2

Total no. of bulb combination = 5C2

=5!/2!(5-2)!

= 5!/2!3!

= 5×4×3×2×1/2×1×3×2×1

=120/12

=10

( since a room can be lighted with one bulb also)

total no. of bulb combination when room shall not light = 3C2

3!/2!(3-2)!

= 3!/2! 1!

= 3×2×1/2×1×1

= 6/2

Now,

Total no. of trial when room shall light

=10-3

Hence, number of trial when the room shall be lighted is 7 which is option d

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a calculator costs 12.99. if its on sale for 20% off and sales tax is 6.25% what is the final cost of the calculator?

wlad13 [49]

I’m pretty sure you can first do 10% at a time which you can round to 13 which is 3 so 3 plus 3 then add tax

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3 years ago

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A system has one each of two different types of components in joint operation. Let X and Y denote the random lengths of the live

RSB [31]

Answer:

The value of E(Y/X) is 2.

Step-by-step explanation:

As the complete question is not given, thus the complete question is found online and is attached herewith.

So the joint density function is given as

$f(x,y)=\left \{ {{\dfrac{x}{8}e^{-\dfrac{x+y}{2}} \,\,\,\,0 \leq x,0\leq y \atop {0}} \right.$

So the marginal function for X is given as

$f_x=\int\limits^{\infty}_0 {f(x,y)} \, dy\\f_x=\int\limits^{\infty}_0 \dfrac{x}{8}e^{-\frac{x+y}{2} }dy\\f_x=\int\limits^{\infty}_0 \dfrac{x}{8}e^{-\frac{x}{2}}e^{-\frac{y}{2} }dy\\f_x= \dfrac{x}{8}e^{-\frac{x}{2}}\int\limits^{\infty}_0e^{-\frac{y}{2} }dy\\f_x= \dfrac{x}{4}e^{-\frac{x}{2}}$

Now

$f(Y/X)=\dfrac{f(X,Y)}{f(X)}\\f(Y/X)=\dfrac{\dfrac{x}{8}e^{-\frac{x+y}{2} }}{\dfrac{x}{4}e^{-\frac{x}{2}}}\\f(Y/X)=\dfrac{1}{2}e^{-\frac{y}{2} }$

Now the value of E(Y/X) is given as

$E(Y/X)=\int\limits^{\infty}_0 {yf_{Y/X}} \, dy \\E(Y/X)=\int\limits^{\infty}_0 {y\dfrac{1}{2}e^{-\frac{y}{2} } }\, dy\\E(Y/X)=\dfrac{1}{2}\dfrac{\sqrt{2}}{(\dfrac{1}{2})^2}=2$

So the value of E(Y/X) is 2.

3 0

3 years ago

Solve using elimination 2x-y=-22 and -7x+y=67 <br> (9,4)<br> (-9,-4)<br> (-4,9)<br> (-9,4)

suter [353]

Answer: (-9,4)

Step-by-step explanation:

2x-y=-22

-7x+y=67

-5x=45

x=-9

2(-9)-y=-22

-18-y=-22

-y=-4

y=4

8 0

3 years ago

The measures of two angles in a triangle are 48° and 71°. What is the measure of the third angle?

qaws [65]

61. 180 minus 71 minus 48 is 61

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3 years ago

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An amusement park studied methods for decreasing the waiting time (minutes) for rides by loading and unloading riders more effic

Digiron [165]

Answer:

see explaination

Step-by-step explanation:

The p-value for Factor A is greater than 0.1

What is your conclusion with respect to Factor A?

Factor A is not significant.

The p-value for Factor B is greater than 0.1

What is your conclusion with respect to Factor B?

Factor B is not significant.

The p-value for the interaction of factors A and B is greater than 0.1

What is your conclusion with respect to the interaction of Factors A and B?

The interaction of Factors A and B is not significant.

What is your recommendation to the amusement park?

Since method is not a significant factor, use either loading and unloading method.

4 0

4 years ago