It is given that Ms N has 2 and a half pints of vinegar and each student needs 3/8 pints of vinegar for the experiment.
Hence the number of students that Ms N can give the vinegar is given by:
Hence the number of students is:

Hence the number of students is:

She can distribute among 6 students and she will have 2/3 pints remaining with her.
The model and the calculation both are wrong in the image
It will be 6 students and 2/3 will remain.