27
Given: Kamal takes twice as long as Amal t_K = 2 * t_A So the AP is: t_A, t_S, 2 * t_A Therefore, the middle term: t_S = (t_A + 2 * t_A) / 2 = 3 * t_A / 2 Now work rates (work per day): Amal: r_A = 1 / t_A Sunil: r_S = 1 / t_S = 1 / (3 * t_A / 2) = 2 / (3 * t_A) = (2/3) * r_A Kamal: r_K = 1 / (2 * t_A) = (1/2) * r_A Given: Amal works 4 days, Sunil works 9 days, Kamal works 16 days and together they finish the whole job So: 4 * r_A + 9 * r_S + 16 * r_K = 1 job Substitute values: 4 * r_A + 9 * (2/3 * r_A) + 16 * (1/2 * r_A) = 1 4r_A + 6r_A + 8r_A = 18r_A = 1 So: r_A = 1/18 t_A = 18 days Sunil’s rate: r_S = (2/3) * (1/18) = 1/27 So Sunil’s time: t_S = 27 days Final Answer: 27 days