Question 1101203
5700=3s*3/4+s
5700=3s*3/4+s
5700=9s/4+s
5700=13s/4
4*5700=13s
4*5700/13=s
1753.84615385=son's share

3/4*4*5700/13=d
3*5700/13=d
1315.38461538=d
check
1315.38461538*3+1753.84615385=5699.99999999
close enough