Question

Using logs, say N = 4 x 1.356^(0.4t)
N = Amount of people.
If there are 1200 people in a school, how long would it take for everyone to know a joke?
How long would it take for 300 people to know a joke?
How many people will know the joke in 1.6 minute?

Answer 1

I think I know how to solve the first 2 q's but not the one for the 1.6 minute one.
Would it be 1200/4 = 1.356^0.4t
--> 300 = 1.356^0.4t
0.4t = log1.356 (base)300
0.4t = log300/log1.356
0.4t= 18.72
t= 47 minutes?

Answer 2

47 min for how long for 300 people to get the joke looks good.
for how many people get the joke in 1.6 minutes, substitute 1.6 for t in the equation and evaluate.
you get 4.86 or about 5 people.

Answer 3

Thank you :)

Answer 4

But actually, wouldn't the 300 q be
300/4 = 75
so 75 = 1.356^0.4t?