Some people enjoy spending their free time alone in activities such as reading, thinking, or writing. Others enjoy spending their free time in shared activities with other people. Which do you prefer and why?

15 in 30

It is not exactly right on the topic. You need to compare about 'alone' or 'group'. The examples are not related to 'alone' or 'group'.

You should get 26 in real TOEFL, since you can talk very fluently. if not, most likely there are something wrong with one of the questions and get get a very low mark.

So read the topic carefully, don't answer something else. No matter how good you are, you never get good marks.