A satisfactory PA chest x-ray is performed on a patient usin…

A satisfactory PA chest x-ray is performed on a patient using manual technical factors of 100 kVp and 8 mAs on a patient that is 28 cm in thickness.  The next patient scheduled for a PA chest x-ray measures 24 cm.  Which of the following sets of technical factors would be optimal in maintaining density and keeping patient exposure to a minimum?