Question 1183508
.
John' speed, 2r
Harry' speed, r


{{{2r*2+r*2=90}}}


{{{6r=90}}}


{{{r=90/6}}}


    r = 15 km/h  --------- Harry' speed


   2r = 30 km/h  -------- John' speed



=============



Solved (correctly)