Amy was born on a Tuesday. What is the probability that exactly two of her three best friends were also born on Tuesday? Express your answer as a common fraction.
What geno said.
It's the probability they are born on a Tuesday versus another day
The probability of being born on a Tuesday is 1/7.
The probability of not being born on a Tuesday is 6/7.
You want to choose 2 out of a possible 3.
3C2 · (1/7)2 · (6/7)1 = your answer
Thank geno! I got 18/343