A space probe of the surface of Mars sends a radio signal back to the
Earth,a distance of 3.79 x 1010 km. Radio waves travel at the
speed of light (3.00 x 108 m/s).
(a) How far away is the space probe?
(b) How many seconds does it take for the signal to reach the Earth?
(c) How many hours is this?

It will vary widley, due to mars being on the same side of the Sun as us, or could be on the other side of the sun.
When you determine the distance you want to use, you cand find hours and seconds.

A space probe of the surface of Mars sends a radio signal back to the
Earth,a distance of 3.79 x 1010 km. Radio waves travel at the
speed of light (3.00 x 108 m/s).
(a) How far away is the space probe?
(b) How many seconds does it take for the signal to reach the Earth?
(c) How many hours is this?


(a) - you are told that the probe is on Mars, and that Mars is 3.79 x 10^10 Km away. So the answer is obvious.
(b) Remember the basic equation for distance, velocity and time: d = v*t. Here you know d (distance) and v (velocity of light, which is 3 x 10^8 m/s), so now you can calculate t (time). This will give t in the unit of seconds.
(c) Convert time in seconds to time in hours by dividing by 3600 seconds per hour.