Question

The mean length of 7 books is 258 pages. the longest book has 294 pages. what is the mean length of the other 6 books?

Answer 1

Think of this situation in this way:

The mean length of 7 books is 258 pages. This is calculated by summing up the lengths of all of the 7 books and dividing the resulting sum by the number of books (7).

Thus,

Sum of number of pages in all 7 books
------------------------------- = average length = 258 pages.
number of books

Now, we're told that the longest book has 294 pages. Here's what we get:

Sum of number of pages in the first 6 books + 294 pages in the 7th book
------------------------------- = average length = 258 pages.
total number of books

Our first goal is to find the sum of the number of pages in the first 6 books.

We have:

Sum of # of pages in the first 6 books + 294
-------------------------------------- = 258
7

1. Multiply both sides of this equation by 7.
2. Subtract 294 from both sides of the resulting equation.
3. simplify.
4. solve for "Sum of # of pages in the first 6 books" by subtracting 294 from both sides.
5. Divide the result by 6. That's your answer: The average # of pages in the first 6 books.

Use a calculator if you have one. The whole problem took just a few keystrokes and less than 1 minute to solve.

Answer 2

Hint to help you with your check: The average # of pages in the 1st 6 books is less than 258.

Answer 3

Wow! Thank you for helping me step by step! I understand how to do this question now! Thank you so much! <3

Answer 4

My great pleasure!