Hey!
First step would be subtract all the money known that he spends from the $25 dollars...
25 - 10 = 15
15 - 10.81 = 4.19
Now with the remaining money you will simply have to use set up an equation..
0.38x = 4.19
Solve for x to get your answer...
4.19/0.38 = 11.03
So Jeff can buy up to 11 packages of peanuts.
Answer: 11 packages
Hope this Helped!
~A