# Four boys and four girls

Four boys and four girls go to a movie theater to see a movie. All the boys sit together and all the girls sit together. All the boys and girls are sitting in 8 adjacent seats. After some time, the lights suddenly go off. The manager of the theater calls 1008990, and after a few minutes, the lights come again. But this time, each boy is sitting next to a girl (i.e., they are sitting in pairs). How did this happen?

Hint

This is a mathematical puzzle. Use a calculator to solve.

• I remember hearing this one in school - as a joke rather than as a puzzle. Not sure if the "logic-puzzle" tag is appropriate. – KeyboardWielder May 14 '16 at 18:52

Let's consider 1 to be boys and 0 to be girls.

Powercut is -(minus) operation.

Then as per the problem
Initial configuration is 11110000
Then power cut. -
Dialed number is 1008990

10101010.

Which is our final configuration.

Each boy was sitting next to a girl from the very beginning:

       ┌──> 8 adjacent seats
┌────┴────┐
│ ┌─┐ ┌─┐ │
┌─┼─┼─┼─┼─┼─┼─┐
│ │ │♂│ │♀│ │ ├──┐
└─┼─┼─┼─┼─┼─┼─┘  │
┌─┼─┼─┼─┼─┼─┼─┐  │
│ │ │♂│ │♀│ │ ├──┤
└─┼─┼─┼─┼─┼─┼─┘  ├──> each boy next to a girl, in pairs
┌─┼─┼─┼─┼─┼─┼─┐  │
│ │ │♂│ │♀│ │ ├──┤
└─┼─┼─┼─┼─┼─┼─┘  │
┌─┼─┼─┼─┼─┼─┼─┐  │
│ │ │♂│ │♀│ │ ├──┘
└─┼─┼─┼─┼─┼─┼─┘
└─┼─┼─┼─┼─┘
└┬┘ └┬┘
│   └──> all the girls sit together
└──> all the boys sit together

• No need to overcomplicate things with the dialed number and binary operations. – Oriol May 15 '16 at 5:04
• Welcome to Puzzling, and great answer! (I appreciate the Unicode art diagram.) – Deusovi May 15 '16 at 6:36
• It's true, adjacent doesn't mean in the same row. You don't win the "you guessed what the OP was thinking" award but you impressed me. – candied_orange May 15 '16 at 19:56

Looks like:

if you add 1008990 to four girls and four boys (00001111) you end up with paired boys/girls, i.e 01010101, since 1008990+1111=1010101

• I think it's cool that this works for 11110000 as well (as said in a previous answer) – ytpillai May 17 '16 at 0:23

I feel like this isn't the answer you're looking for, but I don't see anything in the puzzle that doesn't fit it.

They start in four different rows, two boys sit in first and second rows, two girls sit directly behind in third and fourth rows. When the lights go off the two boys on the left get up, the two girls on the left slide down to the first two rows, and the boys sit back down in the third and forth rows.