Question 373386
Let j = jogging rate, r = riding rate.
Then {{{2j/3 = r/4}}}, or {{{j = 3r/8}}}.  Also r = j + 9.
{{{r = 3r/8 + 9}}},
{{{5r/8 = 9}}}, or r = 14.4 miles per hour, his riding rate.
j = 5.4 miles per hour, his jogging rate.