Answer:
the teacher is correct
Step-by-step explanation:
5:4 totals 9
5/9 of y pupils did their home work
5/9 x y=15
5y=15x9
y =15x9/5
y=27
there are 27 students
next day, 2/3of 27 students did their assignment
2/3 x 27=18
difference between the two days 18-15=3
the teacher is correct