Solve the Problem $5 \mathrm { ft }$ From a Light Is 4 Foot Candles, Find the Intensity

Multiple Choice

Solve the problem.
-The intensity I of light varies inversely as the square of the distance D from the source. If the intensity of illumination on a screen $5 \mathrm { ft }$ from a light is 4 foot candles, find the intensity on a screen 20 ft from the light.

A) $\frac { 1 } { 5 }$ foot-candle
B) $1 \frac { 1 } { 4 }$ foot-candles
C) $\frac { 1 } { 4 }$ foot-candle
D) 2 foot-candles