I think you've got that wrong Caseycouche. I'm sure you will not find any mention of dividing the FLIGHT FUEL by 1.15. You start with the total fuel on board at start-up. Then subtract the taxi and fixed reserve (and any holding fuel). What is left is now 115% of the flight fuel. If you then divide that figure by 1.15, you get 100% of the flight fuel.

Bob

If you check out page 91 to page 93 of the book you will find a detailed introduction to using a variable reserve, along with a number of drill exercises with fully explained answers. These exercises involve finding the minimum total fuel required by adding the reserves and allowances to a known quantity of flight fuel and the reverse calculation of removing all reserves and allowances from a known quantity of fuel on board at start up to find the flight fuel available.

Further exercises specific to the Echo are found on page 99 to page 101. These exercises also have full explanations of the method of working. If these pages are missing from your book, please let me know and I'll send you a replacement.

Bob