Answer: 
Step-by-step explanation:






Formula: P(A or B)=P(A)+P(B)-P(A or B)
p(c)=7/18
p(s)=6/18
p(c or s)=2/18
0.39+0.33-0.11=
answer:0.61
Hey there!
A reciprocal might be an unfamiliar vocab word, but the concept is really quite simple.
It's just a flipped fraction! Multiplying the flipped fraction by it's reciprocal gets you one, and that's how you check your answer.
So we have:
Reciprocal of 9/10 is 10/9, because 9/10 times 10/9 = 90/90 = 1
Reciprocal of 1/11 is 11/1, because 1/11 times 11/1 = 11/11 = 1
Reciprocal of 10(remember, it's 10/1) is 1/10, because 10/1 times 1/10 = 10/10 = 1
Hope this helps!
Answer:
0.049168726 light-years
Step-by-step explanation:
The apparent brightness of a star is
where
<em>L = luminosity of the star (related to the Sun)
</em>
<em>d = distance in ly (light-years)
</em>
The luminosity of Alpha Centauri A is 1.519 and its distance is 4.37 ly.
Hence the apparent brightness of Alpha Centauri A is
According to the inverse square law for light intensity
where
light intensity at distance
light intensity at distance
Let
be the distance we would have to place the 50-watt bulb, then replacing in the formula
Remark: It is worth noticing that Alpha Centauri A, though is the nearest star to the Sun, is not visible to the naked eye.