Mars is about 1.5 times as far from the sun as the earth and its mass is about 0.1 times the earth’s mass. Relative to the gravitational force the sun exerts on the earth, what is the force it exerts on Mars?

The force exerted on Mars is 0.044 times that exerted on Earth using those figures.
The gravitation pull on a body by is given by the equation ##F=(GMm)/r^2## were G is the gravitational constant, M is the mass of the Sun, m is the mass of the planet and r is the distance between the Sun and the planet.
Given that the mass of Mars is 0.1 that of and the distance is 1.5 that of the Earth then the relative force is given by ##0.1/1.5^2=0.0444##.