This scenario can be simulated by generating a set of three numbers using a number generator with numbers 0-9. The numbers 0-6 would represent couples who prefer indoor weddings. If all three numbers in the set are in the range 0-6, it would mean that all three couples prefer indoor weddings.
(ik you might not need this anymore, but I'm hoping it proves useful to others)
if ac is a and bc is b, then ab can be c. now we use Pythagorean method. 16 squared is 156 and 12 squared is 144. added together they are 400. 400 to the square root is 20. Your answer is 20