Sandra wants to buy a dress that is on sale for 20% off. Sandra also gets a 5% discount for being a member of the store's buyer'
s club. Her buyer's club discount is taken off the sale price of any item. If the original cost of the dress was c dollars, which of the following expressions represents what Sandra would pay, in dollars, for the dress?
1 answer:
You might be interested in
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.