Mars has a mean density less than the mean density of the Earth's mantle. How is it possible

that Mars could have a metallic core given this fact? Hint: No calculations are required.
Compare the densities used in part a) with the density of mantle rocks like basalt at one
terrestrial atmospheric pressure.

A metallic core implies having much mass, right? Then the mantle of mars must be really really light for mars to be less dense than even earth's mantle. But how do i show it by comparing density of basalt? As mentioned in the question, i have already determined densities of earth's mantle and core (and also earth's mean density) in another part of the question.

Thanks in advance for any help you can provide.