Question

One week you tell 3 of your friends a secret. The next week, each of them tells 3 people the secret and the next week each of those people tell 3 more people. So the first week, 3 new people know the secret, the second week 9 new people know the secret, the third week 27 new people know the secret, etc. How many people find out the secret on the 4th week?

Answer 1

Answer:81

Step-by-step explanation:

Given

In first week 3 new people Knows the secret and

in second week 9 new people new the secret

and in the third week 27 new people knows the secret

so we can see that each week new people are increasing as power of 3

i.e. $3^n$

where n= no of week

For n=1, it is 3

for n=2,it is 9

for n=3,it is 27

for n=4,it is 81

Answer 2

81 people  will know the secret by week 4