Alrighty then! this is a very tricky kinematics problem but I got the solution for you!!
You need to first find that angle at which the object is traveling downhill by using given distances the the hill and the vertical (y component height).
You should get 10.69 degrees for that angle
Then find the net time it takes for the object to travel all the way down the decline
You should get 1.77 seconds
Then using the given info get the initial velocity_y, final velocity_y , and plug in the net time = 1.77 seconds to find the acceleration_y . (Note the _y just denotes that it is in the y direction (component) of the given info
Then we no no force is exerting in the x component (direction) so the total Force (F_net) = (F_object in y component)
Plug in mass= 50kg, distance= 12.4m, and acceleration_y = 0.587 (meters/(seconds^2))
Work done = Force(distance) = Mass(acceleration_y)(distance) = 363.86 Jewels = answer !!!!