Shipping rate and policy

Sirikot.com a online shopping store provides delivery service for the customers to their door step which depends on various shipping policy to avoid the conflict among its customers. These policies are follows.

Currently Sirikot.com provides shipping service in main sirikot only with the charges of Rs40 per 7kg if the weight exceeds above to 7kg per kg will charged Rs5. For example

If a customer ordered to sirikot.com which weight exceeds to 10kg the delivery charges will be made Rs55. How?

Total weight are 10kg, 7kg charges Rs 40 remaining 3kg charges will be made Rs15 because 3kg exceeded above to 7kg the per kg chargers will apply Rs5 so 3×5=15 Rs which will added to Rs40, so total delivery charges will be made Rs55