Hi there!
In order to answer your question, you'll need to use the cross product method:
84 flyers → 4 minutes
X flyers → 10 minutes
(84 × 10) ÷ 4 = X flyers
840 ÷ 4 = X flyers
210 = X flyers
Your answer is: Alyssa can hand out 210 flyers in 10 minutes.
There you go! I really hope this helped, if there's anything just let me know! :)