Question

plane has 360 total seats, which are divided into economy class and business class. For every 13 seats in economy class, there are 5 seats in business class

Answer 1

Do you need the ratio of Economy to Business?
If so, 18 goes into 360 20 times, so 20 x 5 = 100, and 20 x 13 = 260, so
260:100