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Answer:
0.056 foot-candles
Explanation:
The distance change from 5 m to 9 m is an increase by a factor of 9/5. The light intensity varies as the inverse square of this, so will be multiplied by ...
1/(9/5)² = (5/9)² = 25/81
The intensity at 9 meters will be ...
(0.18 foot-candles) × 25/81 = 0.05555... foot-candles ≈ 0.056 foot-candles