Gst charge

I am Coal Trader not a transporter. I purchase coal from Importer and I manage transporter to load coal from importer place. And then Transporter unload it at my buyer place. Now, Here Importer will charge 5% GST to me and Transporter will charge 18% GST as service to me. For example, Coal Value is 100000 + 5% GST = 105000 and Transport Charge is 10000+18% GST = 11800. Now My total Buying price is 116800 Now Here I sell for value of 120000 than How should I charge rates to my buyers. Should I include my transport cost and charge 5 % GST on value of 120000  OR Should I exclude transport cost and charge 5% GST on cost which is 110000 and Generate another Transport invoice of value 10000 and charge 18% GST to buyer. (Here I am not transporter) If I charge 5% GST on my buying cost which is including Transport cost than  Will I get input Tax Credit of the difference which is 13% on transport value. As I have paid to Transporter 18% GST and I will charge my buyer 5% GST Please guide Thank You