Answer:
Rate of change of profit for this period = $2750 / month
(x,y)
go over x, and up or down y
if fraction then between integers (1/2)=> between 0 and 1.
0=>don't move on that axes
(0,y) move y
(x,0) move x
So we solve for each
70% of 100=70
students who didn't buy lunch=100-70=30
some of the 70 left so that the students who bought lunch, are 60% of those who are left
we know that the students who didn't buy lunch didn't change number so therefor
100% of students left-60%=40%= students that didn't buy lunch=30 so
40%=30
20%=15
100%=75
there were 75 students lfet in the cafeteria
2 - 2 x 3 + 3
= 2 - 6 + 3
= -4 + 3
= -1