It takes 5 minutes to pass a rumor from one form one person to another person. The Tree of Rumour continues. How many persons would know the Rumour after 20 minutes?
A ) 85
B ) 81 ✅
C ) 86
D ) 88
Explanation:
After 5 mins ..... 3 persons will get the rumor After 10 mins .... 3x2 + 3 = 9 persons will get after 15 = 9x2 + 9 =27 after 20 mins..... 27 x2 + 27 = 81