Question 874468
{{{300/(r+12) = 240/r
    {{{300r = 240r + 12*240}}}
    60r = 2880
      r = 48mph, Dustin's speed. Burt's is 60mph
CHECKING our answer***
{{{300/60 = 5 = 240/48}}}
Wish You the Best in your Studies.