Carcass wrote:

The Sun is approximately 1,400 million kilometers from the planet Saturn, and light from the Sun travels to Saturn at the rate of approximately 300,000 kilometers per second. Approximately how many minutes does it take for light to travel from the Sun to Saturn?

A) 80

B) 130

C) 160

D) 280

E) 360

Since 1 million = 10^6, we can re-express the distance from the Sun to Saturn as 1,400 x 10^6 kilometers. We can also express the light’s rate as 3 x 10^5. The time to travel from the Sun to Saturn, in seconds, is:

(1,400 x 10^6)/(3 x 10^5) = (1,400/3) x 10^1 sec = 14,000/3

In minutes, that is (14,000/3)/60 = 14,000/180 = 1400/18 = 700/9 ≈ 80.

Answer: A

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