Let actual marks scored by A and B be 12x and 7x respectively. Difference between the marks scored by A and B = 12x – 7x = 5x According to question, => (7x + 6) × 1.2 = 12x => 8.4x + 7.2 = 12x => 3.6x = 7.2 => x = 2 Required difference = 5x = 10
A 400 m long train crosses a platform twice its length in 2 min. Find the speed of the train.