Answer:
[tex]Math\ Book = 3\frac{65}{72}\ kg[/tex]
Step-by-step explanation:
Given
[tex]Backpack = 18\frac{7}{9}kg[/tex] --- with math book
[tex]Backpack = 14\frac{7}{8}kg[/tex] --- without math book
Required
Determine the weight of her math book
To do this, we simply calculate the difference in the weights given.
Math Book= Backpack(with math book) - Backpack (without math book)
[tex]Math\ Book = 18\frac{7}{9} - 14\frac{7}{8}[/tex]
[tex]Math\ Book = \frac{169}{9} - \frac{119}{8}[/tex]
Take LCM
[tex]Math\ Book = \frac{8 * 169 - 9 * 119}{72}[/tex]
[tex]Math\ Book = \frac{1352 - 1071}{72}[/tex]
[tex]Math\ Book = \frac{281}{72}[/tex]
[tex]Math\ Book = 3\frac{65}{72}\ kg[/tex]
