Calculate how long light travels from the Sun to Neptune. The distance between them is 30 astronomical units.

Calculate how long light travels from the Sun to Neptune. The distance between them is 30 astronomical units. 1 astronomical unit is the distance from the Earth to the Sun, equal to 150,000,000 km. The speed of light is 300,000 km. per second.

First of all, we translate 30 astronomical units into kilometers:
30 astral units = 4 500 000 000 (km)
The second step is to translate 300,000 km / s into km / h
300,000 km / s = 1,079,252,848.8 km / h
Now, substitute and find the time
t = S / V
t = 1,079,252,848.8 / 4,500,000,000 = 0.23 (h)
0.23 (h) = 13.8 (m)
Answer: t = 0.23 (h) = 13.8 (m)