In trapezium PQRS, PQ || SR and the ratio of PQ to SR is 3:2. If the area of the trapezium is 480 cm² and the distance between PQ and SR is 12 cm, then the length of SR is

Let SR = 2x, PQ = 3x. Area of trapezium = (1/2)(PQ + SR) × height = (1/2)(3x + 2x)(12) = 30x. Setting 30x = 480, we get x = 16. So SR = 2x = 32 cm. Hence option (2). Hmm, but answer key shows 36. Let me recompute: (1/2)(5x)(12) = 30x = 480, x = 16, SR = 2(16) = 32. So the answer is 32 cm, option (2).