Question

Eliza's backpack weighs 18 and StartFraction 7 over 9 EndFraction pounds with her math book in it. Without her math book, her backpack weighs 14 and StartFraction 7 over 8 EndFraction pounds. How much does Eliza's math book weigh? 3 and StartFraction 11 over 72 EndFraction pounds 3 and StartFraction 65 over 72 EndFraction pounds 4 and StartFraction 11 over 72 EndFraction pounds 4 and StartFraction 65 over 72 EndFraction pounds

Answer 1

Answer:

$Math\ Book = 3\frac{65}{72}\ kg$

Step-by-step explanation:

Given

$Backpack = 18\frac{7}{9}kg$ --- with math book

$Backpack = 14\frac{7}{8}kg$ --- 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)

$Math\ Book = 18\frac{7}{9} - 14\frac{7}{8}$

$Math\ Book = \frac{169}{9} - \frac{119}{8}$

Take LCM

$Math\ Book = \frac{8 * 169 - 9 * 119}{72}$

$Math\ Book = \frac{1352 - 1071}{72}$

$Math\ Book = \frac{281}{72}$

$Math\ Book = 3\frac{65}{72}\ kg$