How many pages does this book have?

Question

• Michael reads $3$ more pages more than on the last day he read.
• On the 7th day, the amount of the pages he read is $25$.
• If Michael finished reading this book in $10$ days, how many pages does this book have ?.

Before solving this question, I want to understand what question actually means and how to make the correct equations. Can you show it ?.

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My work:

Let's call the pages $x$

$x +(x+3) + (x+6)... (x+21)$

Hence we get

$x+21 = 25 \implies x = 4$

and

$\dfrac{x+(x+30)}{2}.10 = ?$

Regards

Answer 1

Suppose he red $u_1$ pages the first day.

the day two, he red $u_2=u_1+3$.

the $n^{th}$ day, it is $$u_n=u_1+3 (n-1) $$

for $n=7$, we have $u_7=u_1+18=25$

thus $u_1=7$.

after ten days, he will have red $$u_{10}=u_1+9×3=34 pages $$

Directly, seventh day : 25 pages

eighth day :28

nineth day :31

last day :31+3=34.