Yacapaca

A couple of people have written in about this question in the KS4 band:

Here is part of a spreadsheet from a school shop. If the price of a gel pen went up to 60p, which one of the cells listed below would have a new value?

At first glance it may seem that we’ve not programmed the correct answer, but if you read the question again you’ll see it has a twist that you may not have expected…