For a light that has an intensity of 60 candles at its source, the intensity in candles, S, of the light at a point d d feet from the source is given by the formula S=60k/d^2 60, where k is a constant. If the intensity of the light is 40 candles at a distance of 3 feet from the source, what is the intensity of the light at a distance of 20 feet from the source?
Options:
A) 3/10 candles  B) 9/10 candles  C) 1 1/3 candles  D) 2 candles  E) 3 candles
S= 60k/d^2   At 3 feet   40 = 60k/9 so k = 6   At 20 feet   S = 60 *6/20^2 = 9/10   9/10 candles
<result>B</result>
For a light that has an intensity of 60 candles at its source, the intensity in candles, S, of the light at a point d d feet from the source is given by the formula S=60k/d^2 60, where k is a constant. If the intensity of the light is 40 candles at a distance of 3 feet from the source, what is the intensity of the light at a distance of 20 feet from the source?