Start by taking the information we know, and write equations to represent the realationships:
1) "1/8 lbs less flour to make bread than to make cookies"

2) "1/4 lb more flour to make cookies than to make brownies:

3) "she used 1/2 lb of flour ro make bread"

From here you can solve for

using back substitution.
Mushroom only: 4/12 and 1/3
Pepperoni only:6/12 and 2/4
Both mushroom and pepperoni: 2/12 and 1/6
Find percent -> 2nd month.
4264*.25==1066 phone calls+=4264
==5330 for 2nd month.
for 2nd -> 3rd
6396==5330*x, solve algebraically to get .20 == 20% increase from 2nd month to 3rd month.
Im not 100% that thats correct but im pretty sure it is.