sorry, but I can only see the algebra way
in the morning, he sold 24 plus 2/7 of what he had left
what he had left was all-24
2/7 of left was sold
5/7of the ones left=1/2 of all
2/7 of left+24=1/2 of all
therefor
5/7 of the ones left=2/7 of the ones left+24
minus 2/7 of left fro mboth sides
3/7 of the ones left=24
divide both sides by 3
1/7 of the ones left=8
times 7 both sides
ones left=56
left+24=1/2 of all
56+24=1/2 of all
80=1/2 of all
times 2
160=all
he had 160 to start with