For the system $p + q = 11$, $q + r = 13$, and $p + r = 16$, which step is used to find the value of $p + q + r$?

Add all three equations together

Subtract the first equation from the second

Solve for p in the first equation

Multiply the three equations together

Given the system $ab + c = 10$, $ac + b = 12$, and $bc + a = 14$, what expression is the result of adding the three equations?

$ab + ac + bc + a + b + c = 36$