Answer
Find out the what is the ratio of students with pets to students without pets .
To prove
As given
of 60 students, 24 students have a pet.
Thus Total number of student = 60
students have pets = 24
students without pets = 60 - 24
= 36
Now ratio of students with pets to students without pets .

simplify the above

Therefore the ratio of students with pets to students without pets be 2:3 .
Hence proved