Answer:
The number of people who became aware at the time T = 20 days = 2.5 million
Explanation:
p(t) = 5 million
To = 0
T1 = 20 days
P(T1 ) = 50% * 5 = 2.5 million
hence to confirm the value of t where t = 20
P(T1) =

=

= 6 - 4(0.9146)
p(20 ) ≈ 2.5 million