Question 159534
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Remember: {{{Speed=distance/time}}} ---> {{{S=d/t}}}, BASIC EQN
{{{S[1]=12km/hr}}}, canoe paddling
{{{S[2]=5km/hr}}}, hike in scenic trail (walking)
Other points to remember: {{{distance=d=43.25km}}}, {{{t=5.5hrs}}}
In BASIC EQN we get, {{{t=d/S}}}, working eqn
Also, {{{t[1]+t[2]=t}}}. Make sense, time in canoe paddling + time hiking = total time in the trip.
Then as per working eqn,
{{{d[1]/S[1]+d[2]/S[2]=5.5hrs}}} ----------------> eqn 1
But remember too, {{{d[1]+d[2]=43.25km}}} distance in canoe paddling + distance in hiking = total distance in trip ---> {{{d[1]=43.25-d[2]}}},subst, in eqn 1
{{{43.25-d[2]/12+d[2]/5=5.5}}}
{{{5(43.25-d[2]+12d[2])/60=5.5}}}
{{{(216.25-5d[2]+12d[2])/60=5.5}}}, cross multiply
{{{12d[2]-5d[2]=330-216.25}}}
{{{7d[2]=113.75}}}
{{{cross(7)d[2]/cross(7)=cross(113.75)16.25/cross(7)}}}
{{{d[2]=16.25km}}} --------------------> distance travelled in walking
{{{d[1]=43.25-16.25=27km}}} -----------> distance travelled in canoe paddling
In doubt? Go back eqn 1,
{{{27cross(km)/(12cross(km)/hr)+16.25cross(km)/(5cross(km)/hr)=5.5hrs}}}
{{{2.25hrs+3.25hrs=5.5hrs}}}
{{{5.5hrs=5.5hrs}}}
Thank you,
Jojo</pre>