What this question means is that there is a certain number 1x2 that is divisible by 11.
we can simply see what kind of candidates there are. Let's start with 10*11=110.
now, how much is 11*11? it's 121, so not.
12*11? it's 132, and it fits into the question, and the missing number is 3!
so they each paid 12 dollars and gave 132 dollars to the speaker.