Gain from sale of land = cash received from sale of land-book value of land before sale (i.e.bgn value of land)

therefore, cash received=vook value+gain from sale of land=5k+10k=15k.

note:book value is the book value on the land being sold. since the land was sold, the book value was reduced by 5k. therefore, the book value of the land sold was $5k.

no problem. glad to be helpful :-)