The planet Mars is exerting a gravitational pull on you while some person near you also is exerting a gravitational pull on you.
What is the ratio of these two gravitational pulls? (An approximate answer is fine, since, for example, the distance to your friend is likely to change frequently.)
Use Newton’s Law of Gravity to calculate the forces, and then ratio the two forces. Alternatively, and much more easily, if you look at the equation, you’ll see that the ratio for the two forces has the value for ‘G’ and the value for your own mass dividing out, so that the ratio of forces can be simplified considerably.