A worker takes 9 hours to complete a job on daily wages and 6 hours on a scheme of payment by results.

His day rate is Rs 7.50 an hour, the material cost of the product is Rs 40 and the overheads are 150%

of the total direct wages. Calculate the factory cost of the product under

(a) piecework plan,

(b) Rowan plan and

(c) Halsey plan.