Answer:
180seconds
Step-by-step explanation:
From the question, Kepler-186f is an exoplanet that orbits a star called kepler-186, other than the Sun.
Distance of the star (kepler-186) away from the planet is 5.4 x 10^10 meters
To calculate how long i.e. time, a light moving at an average speed of 3.0 x 10^8 m/s will get to the exoplanet from the star, we use the following formula;
Speed (m/s) = Distance (m) ÷ time (s)
Time = Distance/speed
Time = 5.4 x 10^10 ÷ 3.0 x 10^8
Time = 5.4/3.0 × 10^ (10-8)
Time = 1.8 × 10^2
Time = 180seconds.