Question

2、each new number in the pattern shown below was determined by adding the same value to the number just before it. 2,9,16,23... if the pattern continues in the same way, what will be the 8th number? a.30 b.46 c.51 d.56 3、thom is reading a book with 148 pages. he read 26 pages on monday and 35 pages on tuesday. how many pages does he have left to read?

Explanation:

Step1: 确定数列公差

观察数列$2,9,16,23\cdots$，计算相邻数差值：$9-2=7$，$16-9=7$，$23-16=7$，可知公差$d=7$。

Step2: 用通项公式求第8项

等差数列通项公式为$a_n=a_1+(n-1)d$，其中$a_1=2$，$n=8$，$d=7$，代入得：
$a_8=2+(8-1)\times7$
$=2+49$
$=51$

Step3: 计算已读总页数

周一读26页，周二读35页，总已读页数：$26+35=61$

Step4: 计算剩余页数

全书148页，剩余页数：$148-61=87$

Answer:

2、C. 51
3、87