A survey recorded the daily time (in hours) spent online by 60 students. A grouped distribution table is partially filled as shown below:
Class interval (hours): 0–1 | 1–2 | 2–3 | 3–4 | 4–5
Frequency: 8 | y | 18 | 2y | 10
If the total number of students is 60, determine the missing frequencies.