The > sign is a greater/less sign you sure you got the question right?
This kind of sampling is called the Cluster sampling. The cluster sampling method is done by dividing the population by groups called clusters. There will be an equal number of samples drawn from each cluster using simple random sampling. In here, the population are the students which are divided into clusters - by year level. 15 students will be selected from each cluster.
The answer is 48 because you multiple four and 12 because they used twice the amount
