It took Elizabeth 10 days to read a 450-page biography. She read about the same number of pages of the book each day. How many pages did Elizabeth read each day?

Dec 31, 2016

The mean count of pages is 45 per day

Explanation:

Using ratio

$\left(\text{page count")/("day count}\right) \to \frac{450}{10}$

But we need the page count for 1 day. Consequently we need to change the 10 days to 1 day.

Divide both the top and bottom by 10

$\left(\text{page count")/("day count}\right) \to \frac{450}{10} \equiv \frac{450 \div 10}{10 \div 10} = \frac{45}{1}$

Note that $\equiv$ means 'equivalent to'