Question 1142987
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a student goes to school at 2.5km/hr and arrives 6 minutes late. If he travels at 3km/hr he arrives 10 minutes early. 
What is the distance to the school. 
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a student goes to school at 2.5km/hr and arrives {{{1/10}}}{{{hour}}} late. If he travels at 3km/hr he arrives {{{1/6}}}{{{hour}}} early. 
What is the distance to the school. 
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<pre>
              SPEED       TIME        DISTANCE
SLOW          2.5         x+1/10       d
FAST          3.0         x-1/6        d
</pre>


{{{2.5(x+1/10)=3(x-1/6)=d}}}

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{{{30*2.5(x+1/10)=30*3(x-1/6)}}}

{{{75(x+1/10)=90(x-1/6)}}}

{{{75x+7.5=90x-15}}}

{{{15x=22.5}}}
{{{30x=45}}}
{{{x=3/2}}}--------the usual travel time, hours


{{{d=3(x-1/6)}}}

{{{d=3(3/2-1/6)}}}

{{{d=3(9/6-1/6)=3(8/6)}}}

{{{d=8/2}}}

{{{highlight(d=4)}}}---------distance to school, km