Question 964363
Let t be the expected time;
Let d be the distance from A to B.
10 minutes is {{{1/6}}} hour;
16 minutes is {{{4/15}}} hour.



___________________speed____________time_____________distance________Equations
Late_______________40_______________t+1/6____________d_______________{{{40(t+1/6)=d}}}
Later______________30_______________t+4/15___________d_______________{{{30(1+4/15)=d}}}


That should be enough for you to continue to the finish.  Two equations and two unknown variables.