题目
Problem
An arithmetic progression has fourth term 15 and eighth term 25.
Find the 30th term of the progression.
[3]
题目中文翻译
一个等差数列的第 4 项为 15，第 8 项为 25。
求该数列的第 30 项。
An arithmetic progression has fourth term 15 and eighth term 25.
Find the 30th term of the progression.
一个等差数列的第 4 项为 15，第 8 项为 25。
求该数列的第 30 项。