Question 919497
Let {{{ s }}} = th speed of the boat in mi/hr 
in still water
Let {{{ c }}} = the speed of the current in mi/hr
--------------
Equation for going downstream:
(1) {{{ 230 = ( s + c )*10 }}}
Equation for going upstream:
(2) {{{ 230 = ( s - c )*46 }}}
------------------------
(1) {{{ 10s + 10c = 230 }}}
(2) {{{ 46s - 46c = 230 }}}
------------------------
Add the equations:
(1) {{{ s + c = 23 }}}
(2) {{{ s - c = 5 }}}
------------------
{{{ 2s = 28 }}}
{{{ s = 14 }}}
and, since
(1) {{{ s + c = 23 }}}
(1) {{{ 14 + c = 23 }}}
(1) {{{ c = 9 }}}
The speed of the boat 
is 14 mi/hr in  still water
The speed of the current is 9 mi/hr
--------------
check:
(1) {{{ 230 = ( 14 + 9 )*10 }}}
(1) {{{ 230 = 230 }}}
OK -you can check other equation