Boy or Girl?

Will the witch make a profit or loss?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

Problem



A witch claims that she can predict whether your baby will be a boy or girl, and she charges £100 for this service.

If her prediction is wrong, she offers to return your £100 fee and pay you an extra £50 compensation for any distress that she may have caused.

Assuming she does not have any supernatural powers, can you explain whether she is likely to make a profit or loss after 100 clients have given birth? 

If you liked this problem, you might also like the article it appears in, Con Tricks