three machines are needed to process a unit of a product. the product must be processed by machine a before going to machine b and machine c there are two machine bs and two machine c in the process machine a has a processing time of $2$ minutes per piece machine b has a processing of $1$ minute per unit and machine c has a processing time of $2$ minutes per unit. handling time per move is equivalent to $1$ minute. since there are two machines b and c in the process, the company does not allow transporting single unit to every process assume the machines would process $10$ units and the company incurs php $7$ per minute and php $4$ per move