KCF the actual rates for Aramex are as follows

39 QAR for thr first 0,5 Kg (500 grs)

31 QAR for every additional 0,5 Kg (500 grs)

So in the case you mention it is like this

first 0,5 Kg equals 39 QAR

the remaining 5,0 Kg is like 62 QAR X 5 Kg equals to 310

adding up you get 310+39= 349 QAR

Best regards