module 3 light intensity questions (1 Viewer)

[fx82au]

can anyone help with the following question:

answer is apparently A, but all my working out leads to C

 

[fx82au]

i understand c logically makes no sense, and a is just 1/2.3... but i just want to know the correct working out

 

[fx82au]

now i just feel like an idiot :/

here i think is the correct working i think... just mixed up my variables


heres the question for a future students google search:
8 The Earth is approximately 150 × 106 km from the Sun, and Mars is a further 78 × 106 km from Earth. How much is the intensity of light from the Sun reduced at Mars compared to Earth? A The intensity of light at Mars is 0.4 times the intensity at Earth. B The intensity of light at Mars is 0.2 times the intensity at Earth. C The intensity of light at Mars is 2.3 times the intensity at Earth. D The intensity of light at Mars is 0.3 times the intensity at Earth.