It makes sense if they are printing more - it will take more time.
This is a simple ratio problem. Think o t almost like a sped - like miles per hour (mi/hr) - except you have dictionaries per minute:
14 dict / 12 min = x dict / 30 min
Write those slanted fractions up and down, and you will see one way to solve is to cross multiply:
14/12 = x/30
12x = (14)(30)
x = (14)(30)/(12)