Question

Each chapter in Zenni's book has exactly 21 pages. There are 15 chapters and Olivia has read 7 chapters. How many total pages does Olivia have left?147168315420

Answer 1

According to the information given in the exercise, Olivia's book has 15 chapters of 21 pages each. Then, the total number of pages the book has is:

`\begin{gathered} Pages_{\text{book}}=15\cdot21 \\ Pages_{\text{book}}=315 \end{gathered}`

You know that Olivia has read 7 chapters. Then, you need to multiply 7 by 21 in order to calculate the number of pages Olivia has read so far. This is:

`\begin{gathered} Pages_{\text{read}}=21\cdot7 \\ Pages_{\text{read}}=147 \end{gathered}`

Based on the above, you can calculate the number of total pages Olivia has left by finding the difference between the total number of pages the book has and the number of pages she had read. Then, you get:

`\begin{gathered} Pages_{\text{left}}=315-147 \\ Pages_{\text{left}}=168 \end{gathered}`

The answer is: Second option.