Questions 26–30 are worth 6, 7, 8, 9 and 10 marks, respectively.
26. Let A be a 2018-digit number which is divisible by 9. Let B be the sum of all digits of A and C be the sum of all digits of B. Find the sum of all possible values of C.
27. The trapezium ABCD has AB = 100, BC = 130, CD = 150 and DA = 120, with right angles at A and D.