Question 364791
Let {{{s}}} = his rate swimming in km/hr
Let {{{r}}} = his rate running in km/hr
given:
(1) {{{s*(3/4) + r*(1/3) = 9}}} km
(2) {{{s*(1/2) + r*(2/3) = 14}}} km
Multiply both sides of (1) by {{{12}}}
and both sides of (2) by {{{6}}}
(1) {{{9s + 4r = 108}}}
(2) {{{3s + 4r = 84}}}
Subtract (2) from (1)
(1) {{{9s + 4r = 108}}}
(2) {{{-3s - 4r = -84}}}
{{{6s = 24}}}
{{{s = 4}}}
and
(2) {{{3*4 + 4r = 84}}}
{{{4r = 84 - 12}}}
{{{4r = 72}}}
{{{r = 18}}}
He swims 4 km/hr and runs 18 km/hr