Guys I doubled checked question 7 (trial and improvement) and it was in fact 3.8. The reason why is because you had to use the tester value 3.75. Once you got the answer you would have found the answer was too small, so you go for the opposite which in this case was 3.8 as it was bigger. If you havent included the tester value of 3.75, you have lost a mark, and if you put the answer as 3.7 you again have lost a mark. However 3 marks are still enough for a 4 marker to be fair