Apro baseball team is having a promotion in which every 10th fan that enters the stadium gets a free hat and every 12th person gets a free t-shirt . how many fans will come into the stadium before a fan receives both a hat and a t- shirt ?

Multiples of 10 = 10, 20, 30, 40, 50, 60
This means the 10th, 20th, 30th, 40th, 50th, 60th, ... fan will get a free hat.
Multiples of 12 = 12, 24, 36, 48, 60
This means the 12th, 24th, 36th, 48th, 60th, ... fan will get a free shirt.
So the 60th fan will receive both a hat and a shirt.
Meaning 60 fans will come to the stadium before a fan receives both a hat and a shirt.

Iam thinking the answer is a.) knew