The mass of an object is 90 kg. If the mass of Mars is one-sixth the mass of the earth, what is the weight of the object on Mars?

The weight of the object on mars will be $147\mathit{ N}$.
Given,
Mass of the object, $m=90\mathit{ kg}$
Weight of the object, $\mathrm{W}=\mathrm{mg}$
                                        $=90\times 9.8$
                                        $=882\mathit{ N}$
The amount of matter that makes up an object is its mass. It is a scalar quantity. In contrast, a body is drawn toward the centre of the earth by the force of an object's weight. It is a vector quantity that is oriented toward the earth's centre. 

The formula, $\mathrm{W}=\mathrm{mg}$

Where, $m$ is the object's mass, and $g$ is its gravitational acceleration, can be used to determine the weight. 

The mass of an object is constant, while the weight of an object varies with the variation in acceleration due to gravity.
The ratios of the weight of an object on earth to the weight of an object on the moon can be calculated as
$\frac{{\mathrm{mg}}_{\mathrm{e}}}{{\mathrm{mg}}_{\mathrm{m} }}=\frac{{\mathrm{g}}_{\mathrm{e}}}{{\mathrm{g}}_{\mathrm{m} }}$
$\Rightarrow \frac{9.8}{1.7}=6$
The weight of the object on the moon  $=\frac{1}{6}\times \mathrm{weight} \mathrm{of} t\mathrm{he} \mathrm{object} \mathrm{on} earth$
$=\frac{1}{6}\times 882$
$=147\mathrm{N}$