The function d (t) = 300,000t represents the distance (in kilometers) that light travels in t seconds.

a. How far does light travel in 15 seconds?

kilometers

b. How long does it take light to travel 12 million kilometers?

seconds.

a. The light travels 4,500,000 kilometers in 15 seconds

b. It takes the light 40 seconds to travel 12 million kilometers

Step-by-step explanation:

- The function d (t) = 300,000 t represents the distance in kilometers

that light travel in t seconds

a.

- We need to find how far the light travels in 15 seconds

∵ d (t) = 300,000 t

∵ t = 15 seconds

- Substitute the value of t in the function above

∴ d (t) = 300,000 (15)

∴ d (t) = 4,500,000 kilometers

The light travels 4,500,000 kilometers in 15 seconds

b.

- We need to find how long does it takes the light to travel 12 million

kilometers

∵ d (t) = 12 million kilometers = 12,000,000 km

∵ d (t) = 300,000 t

- Substitute the value of d (t) in the function

∴ 12,000,000 = 300,000 t

- Divide both sides by 300,000

∴ t = 40 seconds

It takes the light 40 seconds to travel 12 million kilometers