K.T

the average of final exam is 64, the standard deviation is 7. If the teacher set a rule that 1/4 of students who receive the poor grades should stay after class. lower than what mark should the students stay in school? does anyone know how to solve this?

my friend came out with the following solution. P(Z<-0.675)=0.25 -0.675= (X-64)/7 but i'm kinda confused. where did the 0.675 come from?

Still need answers to 4, 9, 12, 13, and 20

Still need9) I was too busy with other thoughts to notice that they were muddy when they returned back home. 13) We must persevere and not be implicated in wrong doing as we push ahead in this fight.