D because a has to be younger than 18 and it has to be positive because we are never a negative age. do you understand when i mean?
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Step-by-step explanation:
d if not d a.................
B) 36
To figure this out you need to average the numbers. To average them you add them all up and divide by how many are there.
(60+30+20)/3
(90+20)/3
110/3
36
