(a) Amit&Benn, both score 35 marks Let’s say both got x correct and y wrong. So 4x - y = 35 & x + y =10 ⇒ x = 9,y = l So both Amit & Benn got 9 questions correct and 1 question wrong. So we can see that Chitra got 4 questions correct (Q1, 2, 3,9) Hence score of Chitra = 4 x 4 - 6 = 10.