Kinematics: uniform rectilinear motion

@REM Time function is not working properly (yet)

::Example::
::If there is a straight section of highway 120 Km between them and Joe travels south towards
::Bob at 30Kph while Bob travels north towards Joe at 25Kph how long will it be before they
::meet and how far will each have traveled in that time?

::https://www.facebook.com/groups/ILMFP/

::Joe:
        ::Starting distance: 0
        ::Starting time: 0
        ::Speed: 30
::Bob:
        ::Starting Distance: 120
        ::Starting time: 0
        ::Speed: -25 (negative because Bob is going to Joe)
::Output:
    ::Meeting time: 2,181 h
    ::Distance Joe: 65.430 km
    ::Distance Bob: 54.525 km

@REM I <3 Math for programming!
@REM (c) Robin "yugecin" Claerhout
@echo off
:a
call:table "1"
set /p a=ÈÍ^>
if not defined a goto a
:b
call:table "2"
set /p b=ÈÍ^>
if not defined b goto b
:c
call:table "3"
set /p c=ÈÍ^>
if not defined c goto c
:d
call:table "4"
set /p d=ÈÍ^>
if not defined d goto d
:e
call:table "5"
set /p e=ÈÍ^>
if not defined e goto e
:f
call:table "6"
set /p f=ÈÍ^>
if not defined f goto f
cls

if %c% LSS %f% (
    if %a% LSS %d% (
        echo They will never meet!
        pause
        goto a
    )
)

::%a% sdistance joe
::%b% stime joe
::%c% speed joe

::%d% sdistance bob
::%e% stime bob
::%f% speed bob

::ERB joe = sdistance + speed*t - speed*stime
::        = %a% + %c%*t - %c%*%b%

::ERB bob = sdistance + speed*t - speed*stime
::        = %d% + %f%*t - %f%*%e%

:: %a% + %c%*t - %c%*%b% = %d% + %f%*t - %f%*%e%
::       (%c%-%f%)*t     = %d% - %a% - %f%*%e% + %c%*%b%
::                 t     = (%d% - %a% - %f%*%e% + %c%*%b%)/(%c%-%f%)
set /a a*=1000
set /a b*=1000
set /a c*=1000
set /a d*=1000
set /a e*=1000
set /a f*=1000

set /a t=(%d% - %a% - %f%*%e% + %c%*%b%)/(%c%/1000-%f%/1000)
if %t% GTR 999 (
echo Meeting time: %t:~0,1%,%t:~1,3% h
) else (
    if %t% GTR 99 (
        echo Meeting time: 0.%t% h
    ) else (
        echo Meeting time: 0.0%t% h
    )
)
::if %c% LSS 0 set /a c*=-1
::if %f% LSS 0 set /a f*=-1
set /a i=%c%*%t%
set /a j=%f%*%t%
set /a i/=1000
set /a j/=1000
if %i% LSS 0 set /a i*=-1
if %j% LSS 0 set /a j*=-1
rem set /a i=%a%-%i%
rem set /a j=%d%-%j%
rem if %i% LSS 0 set /a i*=-1
rem if %j% LSS 0 set /a j*=-1

if %i% GTR 99999 (
    echo Distance Joe: %i:~0,3%.%i:~3,7% km
) else (
    if %i% GTR 9999 (
        echo Distance Joe: %i:~0,2%.%i:~2,5% km
    ) else (
        if %i% GTR 999 (
            echo Distance Joe: %i:~0,1%.%i:~1,3% km
        ) else (
            if %i% GTR 99 (
                echo Distance Joe: 0.%i% km
            ) else (
                echo Distance Joe: 0.0%i% km
            )
        )
    )
)

if %j% GTR 99999 (
    echo Distance Bob: %j:~0,3%.%j:~3,3% km
) else (
    if %j% GTR 9999 (
        echo Distance Bob: %j:~0,2%.%j:~2,3% km
    ) else (
        if %j% GTR 999 (
            echo Distance Bob: %j:~0,1%.%j:~1,3% km
        ) else (
            if %j% GTR 99 (
                echo Distance Bob: 0.%j% km
            ) else (
                echo Distance Bob: 0.0%j% km
            )
        )
    )
)

pause
goto a

exit /b


:table
setlocal
cls
echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍËÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
echo º              Joe          º     Bob                 º
echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÎÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ͹
set "a= Starting distance (km)"
if "%~1" EQU "1" set "a=^>Starting distance (km)"
set "b= Starting distance (km)"
if "%~1" EQU "4" set "b=^>Starting distance (km)"
echo º %a%   º %b% º
set "a= Starting time (h)"
if "%~1" EQU "2" set "a=^>Starting time (h)"
set "b= Starting time (h)"
if "%~1" EQU "5" set "b=^>Starting time (h)"
echo º %a%        º %b%      º
set "a= Speed (km/h)"
if "%~1" EQU "3" set "a=^>Speed (km/h)"
set "b= Speed (km/h)"
if "%~1" EQU "6" set "b=^>Speed (km/h)"
echo º %a%             º %b%           º
echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÊÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ
endlocal
GOTO:EOF