Question 1100999
<pre>
BUS          SPEED     TIMES          DISTANCE
A            r         300/r           300
B            r+10      300/(r+10)      300
DIFFERENCE             {{{1&1/4}}}
</pre>



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Bus B travelling at an average speed of 10km/hr greater than that of A reached S One and a quarter hours earlier.
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{{{300/r-300/(r+10)=1&1/4}}}

-

{{{300/r-300/(r+10)=5/4}}}

{{{60/r-60/(r+10)=1/4}}}

{{{240/r-240/(r+10)=1}}}

{{{240r+2400-240r=r^2+10r}}}-----------

{{{r^2+10r-2400=0}}}


{{{r=(-10+sqrt(9700))/2}}}

{{{r=(-10+10*sqrt(97))/2}}}

{{{r=-5+5*sqrt(97)}}}



{{{highlight_green(r=44.2)}}} {{{km/hour}}}