Question 3
Alex and Charles were both sending parcels. The postage rates are as follows: For the first 10 kg and below, the postage price is 6 dollars per kg; for each successive kilogram after 10 kg, the postage price per kg is slightly lower than that of the first 10 kg. It is known that the weight of Alex’s parcel is 20% heavier than Charles’ parcel, and that the postage prices for Alex and Charles are 92 dollars and 80 dollars respectively. How much more is the postage price per kg of the first 10 kg than that of each succeeding kg above 10 kg?