The intensity (I) of light received at a source varies inversely as the square of the distance (d) from the source. If the light intensity is 98 foot-candles at 27 feet, find the light intensity at 9 feet.

Question

saifoo.khan · Answer

$$I = \frac{k}{d^2}$$

$$98 = \frac{k}{27^2}$$

k = 71442

saifoo.khan · Answer

$$I = \frac{71442}{9}$$

I = 7938

anonymous · Answer

The correct answer was 882?? Oh man I hate these problems!!

dumbcow · Answer

saifoo is correct in the set up
just forgot to square the 9
71442/81 = 882

saifoo.khan · Answer

Ohhh!
SORRYY!