Answer:
The sum of the age of pupils is 81
Step-by-step explanation:
Let sum of age of 18pupils = x
Average ages = 4.5
Average = total/no. of pupil
4.5 = x/18
x = 81
<h2>YOUR ANSWER IS IN THE ATTACHMENT PLZZ REFER TO THE ATTACHMENT </h2>
<h2>FOLLOW ME FOR CLEARING YOUR NEXT DOUBT </h2><h2>MARK ME BRAINLIEST </h2>
<span>As only one team is to be made that means we have to choose 2 people from total 13 people. As the order that two people are selected does not matter here so we just have to make all possible combination of the team
So the answer is 13*12/2
answer= 78 ways</span>