Haley and Sabrina are both training for a race.

Haley runs 4.2 miles each day.
Sabrina has been running 4.2 as many miles each day as Haley.
Next week, Sabrina is going to increase the miles she runs each day by 25%.
Haley and Sabrina both train by running 6 days each week.
What is the total number of miles Sabrina will run next week to train for the race?