Question 1161107
r, Hector's speed


{{{3(r/0.7)+3r=30.6}}}
-
{{{3r+3*0.7r=30.6*0.7}}}
{{{3r+2.1r=21.42}}}
{{{5.1r=21.42}}}
{{{r=21.42/5.1}}}
{{{highlight(r=4.2)}}}


{{{cross(r=6)}}}