Decimal problem using solve

[Albert Chan]

Hi, vterez:

I thougt that was a math class problem ...

I dont know HP Prime, but Mathematica have similar issue.
Decimals were assumed inexact, and use fast float.

This force Mathematica to solve it exactly:

Code:

Solve[ Rationalize @ {
    70/(23000+z) == (177.35 x + 1.133 (1-x)),
    (23000+z)*(2571.11 x + 696.21 (1-x)) == 23000*104.91 + 2779.65 z
  }, {x, z}
]