I think you may find that the pass mark is about 50% but to get 140 it is considerably higher, ie about 75% ish. The following is information from my son's school's website:
The Kent Tests â€“ Information for Parents
The maximum score in any of the Kent PESE tests is 140, but this does not equate to 100%.
Historically, the score of 140 equates to approximately 75% on any one test.
A minimum selective score of 120 equates to approximately 50%. The tests are in:
Verbal Reasoning (80 questions)
Non-Verbal Reasoning (72 questions)
Mathematics (50 questions)
Figures are approximate because older children in the year group needed to gain a slightly
higher % than this, whilst younger children could gain a slightly lower %. In addition, there is
a variation from year to year.