Answer:
We have been given the sum of three numbers is 855:
x+y+z=855
And x, is 50%, more than the sum of the other two numbers:
[tex]x=\frac{50}{100}+y+z[/tex]
[tex]x=\frac{1}{2}+y+z[/tex]
[tex]\Rightarrow 2x=y+z[/tex]
Substitute y+z=2x in x+y+z=855
2x+x=855
On simplification:
3x=855
x=285
Hence, the value of x is 285.