Variations in planetary gravity?

Mars has 38% of earth's gravity (9.8m/s^2). A Martian is lost and does not know what planet he is on. He knows that certain pendulum that he owns has a period of 1.5s on Mars. (A) How long is his pendulum? - If he find that on a planet that he is now on the period is .92s (B) what is the gravity of this planet? (C) Is there any planet in this solar system where the Martian might be?