If you would like to know how many students are likely to have pet dogs, you can calculate this using the following steps:
24 students have pet dogs ... 60 students
x students have pet dogs = ? ... 490 students
24 * 490 = 60 * x /60
x = 24 * 490 / 60
x = 196 students
Result: 196 students are likely to have pet dogs.