Observing the answers of A and B, we can see that A and B have the same answers to four questions, but different answers to six questions. Because everyone is 70 points, four questions with the same answer are all right, and three questions with different answers are all right. Therefore, the answers to the questions 1, 3, 4 and 10 are ×, √ and × respectively;

Similarly, according to B and C, the answers to questions 2, 3, 5 and 7 are ×, √, √ and √ respectively;

According to A and C, there are also four questions with the same answers. The answers to questions 3, 6, 8 and 9 are √, √, ×, √ respectively;

To sum up, the answers to the question 1 ~ 10 are × ,×, √, √, √, ×, ×.

According to D's answer, D's answers to questions 2, 3, 6, 9 and 10 * * are wrong, and 50 points are scored.

So the answer is: 50.