A shipping company sets its charges by applying the following rule;

 A fixed cost of K170.50 is charged for cargo handling.

 A charge of K12.50 is added for every kilometre of the length of the journey covered in

transporting the cargo to its final destination.

 A variable charge is added to cover tracking and insurance. This charge is K85.00 for ports

less than 100km apart, K115.00 for ports between 100km and 500km inclusive and K150.00

for ports over 500km apart.

Let = cost of transporting cargo between two ports and = distance between the ports

a) Construct a multiple formula for this function.