How do i solve this when using the foil method (5r+13)(r+2)

Firstly, you have to know what FOIL stands for.
F= first
O= outside
I= inside
L= last

So to solve you start with the first two numbers of each of the equations in parentheses (5r and r) which will equal 5r^2 

outside is 5r and 2 which equals 10r

inside is 13 and r which equals 13r

last is 13 and 2 which is 26

then you have 5r^2, 10r, 13r, and 26

add common characters and you'll have 5r^2+23r+26

9sandwiches per hour