2. a) The average age of 5 students is 9 years. Out of them the ages of 4 students are 5, 7, 8 and 15 years. What is the age of the remaining student?

Answer:
10
Step-by-step explanation:
5 * 9 = 45
45 is the sum of all the ages added up
45 - (5 + 7 + 8 + 15) = 10