Question 558130
<br>
NOTE:
Outbound <---> going
Inbound <---> returning<br>
Let x be the lower speed (on the return trip, which took longer)
Then x+144 is the outbound speed<br>
The distances (rate times time) are the same:<br>
{{{9(x)=5(x+144)}}}
{{{9x=5x+720}}}
{{{4x=720}}}
{{{x=180}}}<br>
The speed on the return trip was x=180 km/hr; the speed on the outbound trip was x+144 = 324 km/hr.<br>
ANSWER: 324 km/hr<br>
An alternative way to set up the problem is to write an equation which says that, because the distances are the same, the ratio of speeds is equal to the ratio of times.  The initial equation is different; but it leads immediately to the same calculations to solve the problem.<br>
{{{(x+144)/x=9/5}}}
{{{9x=5(x+144)}}}<br>
And from there the solution is the same as above.<br>