The weight of any person on the moon is about $\frac{1}{6}$ times that on the earth. He can lift the maximum mass of 15 kg on the earth. What will be the maximum mass, which can be lifted by the same force applied by the person on the moon?

Given, 

${\mathrm{g}}_{\mathrm{e}}=\mathrm{g}$ and ${\mathrm{g}}_{\mathrm{m}}=\frac{\mathrm{g}}{6}$

$g_{e }$= earth's gravity ; $g_{m }$ = moon's gravity; g= acceleration due to gravity

Force applied to lift a mass of 15 kg at the earth

 $\mathrm{F} = {\mathrm{mg}}_{\mathrm{e}}= 15 {\mathrm{g}}_{\mathrm{e}}$

If he can lift a certain mass ‘m’ by applying the same force on the moon, then

$\mathrm{F} = {\mathrm{mg}}_{\mathrm{m}}$

$\mathrm{m} = \frac{\mathrm{F}}{{\mathrm{g}}_{\mathrm{m}}}=\frac{15{\mathrm{g}}_{\mathrm{e}}}{{\mathrm{g}}_{\mathrm{m}}}=\frac{15 \mathrm{g}}{9/6}= 90 \mathrm{kg}$

 m= 90kg

The person will be able to lift a weight of 90 kg on the moon.