This question is a masterpiece of "anti-logic" game design. Here is why it is a fascinating topic for a post:
What starts with an E, ends with an E, but only contains one letter? deal or no deal impossible quiz answer
Some rounds feature a "bomb" timer that requires a split-second reaction. Key Answers for Difficult Rounds This question is a masterpiece of "anti-logic" game design
The equation 10 + 10 + 10 - 10 = 20 is a red herring. The developers knew players would spend minutes hunting for the number 20 or trying to convert the math into British pounds. The solution requires you to step back, ignore the math, and click the button that lets you keep playing. ends with an E