Answer:
90 minutes
Explanation:
Given that:
Duration of advert shown per half hour = 3 minutes
3 minutes per 30 minutes = 3 / 30
Number of minutes from 8am to 11pm = 15 hours = (15 * 60) = 900 minutes
3minutes per 30 minutes = x per 900 minutes
3/30 = x / 900
Croas multiply :
30x = 900 * 3
30x = 2700
x = 2700/30
x = 90
Hence, 90 minutes of advert between 8am to 11pm