Physics problem: find work

Question

A sled of mass 10 kg went down from a hill of height 5 m and stopped at the horizontal part of a road. Find the work done when dragging the sled up the hill. Answer is 1000 J

Answer 1

Work A₁ agaist resistance A₁ = - mgh = - 10kg·9.8 m/s²·5m = 490 J

Then if we move it back we have to compansate work against resistance and move up to give potential energy. So, A = A₁ + mgh = 490j + 490J = 980 J