SOLUTION: Patsy can do 1/4 of a work in 10 days. Quincy can do 40% of the work in 15 days and Rhonda can do 1/3 of the work in 13 days. Who will complete the work first?

So when Patsy's finishes doing that 1 fourth of the work, she'll have 3 fourths
left to do, so that'll take her 3 times as long as it took her to do 1 forth, 
so it'll take her 3 times 10 or 30 days.  

So he can do 80% of the work in 30 days.  And he can do the other 20% of the
work in half the time it takes him to do the first 40%, which is half of 15
days or  days.  So altogether it will take him  days.
That's longer than it takes Patsy. 

So when Rhonda finishes doing 1 third of the work, she'll have 2 thirds
left to do, so that'll take her 2 times as long as it took to do the 1 third,
so it'll take her 2 time 13 or 26 days.

So:
It'll take Patsy 30 days
It'll take Quincy  days
It'll take Rhonda 26 days.

So Rhonda will finish first.  Patsy will come in second and
Quincey will bring up the rear.  (In math problems I've noticed
that girls out-do boys a lot more than boys out-do girls.)

Edwin