### 89

You step closer to the door and carefully examine the combination lock. You are confident that, with your skill and experience, you will soon have it open without too much difficulty.

Study the following sequence of numbers. When you think you have worked out what the missing number is turn to the page which is identical to your answer.11

If you guess incorrectly, or if you cannot solve the door puzzle, turn instead to 30.

[11] The section corresponding to the correct answer will have a footnote confirming that it is indeed correct.

Text copyright © 1991 Joe Dever.
Illustrations copyright © 1991 Brian Williams.