posted by Joe .
The week before a big concert, five friends (Alvin, Bert, Chip, Dennis, and Ethan) stood in line to buy tickets. There were other people between them, but the five friends were in line in the order listed above.
The line was really long, and they were pretty bored. Chip noticed that if he counted the number of strangers between each pair of friends, he got the numbers 7, 12.19, 21 36, 43, 55, 57, 64, and 76. Like I said, he was REALLY bored.
He sent the information to Ethan in a text message, and Ethan passed the time in line using Chip's information to determine how many people were between Alvin and Bert, between Bert and Chip, betwen Chip and Dennis, and between Dennis and Ethan. What did he find?
Since Chip is in the middle, we don't know if the interposed customers are in the respective order.
If they are, then it seems there are 7 between Alvin and Bert 12 between Bert and Chip, 19 between Alvin and Chip (counting or not counting Bert?) and so on.
With the above lack of data, I am not sure of my response.