Question 253285
Let H be the hundreds digit
Let T be the tens digit
Let U be the units digit.

We are given the following:

{{{T+3=5U}}}  (1)
{{{3(H+T+U)-2=4H}}}  (2)
{{{100U+10T+H=100H+10T+U-594}}}  (3)

Rearrange (1) to equal T. Then substitute into (2).

{{{3(H+(5U-3)+U)-2=4H}}}
{{{3(H+6U-3)-2=4H}}}
{{{3H+18U-9-2=4H}}}
{{{3H+18U-11=4H}}}
{{{18U-11=H}}} (4)

Collect terms in (3) to give {{{99U-99H=-594}}} (5)

Subsitute (4) into (5) to give {{{99U-99(18U-11)=-594}}}
{{{99U-1782U+1089=-594}}}
{{{-1683U+1089=-594}}}
{{{-1683U=-1683}}}
{{{U=1}}}

Plug this result into (1) and (4) to give {{{T=8}}} and {{{H=7}}}

So the original number 781.

Does that make any sense?