Question 637973
given:
{{{ d[c] = 80x }}} km
{{{ d[b] = 13 + 80x }}} km
{{{ d[b] = 2d[c] }}} km
{{{ 13 + 80x = 2*80x }}} *
{{{ 13 + 80x = 160x }}}
{{{ 80x = 13 }}}
{{{ x = 13/80 }}} hrs
-----------
* you just wrote this backwards