It is known that A's money is half that of the other three, so A's money is one third of the total.

Similarly, B's money is a quarter of the total and C's money is a fifth of the total, so D's money is1-1/3-1/4-1/5 =13/60 of the total.

The total amount of money is 9 10 divided by 13/60=4200 (yuan).

A x，b y，c z

x=0.5*(9 10+y+z)

y=(x+z+9 10)/3

Z=(x+y+9 10)/4

x= 1400

y= 1050

z=840

x+y+z+9 10=4200