Weight is another term for the force from mass multiplied by acceleration due to gravity, the equation being expressed as \(f = ma\), being force, mass, and acceleration respectively.
We already have 2 parts of the equation,\(50 = 10a\)
Acceleration due to gravity on the planet is \(5 m/s^2\)
Plug it into the equation \(f = ma\)
\(f=6kg\) x \(5m/s^2\)
Weight or force from gravity is 60N.