The distance between A and B is 785 kilometers. Two cars A and B are driving towards each other from A and B at the same time. It is known that car A travels an average of 79 kilometers per hour. After 4.5 hours, the distance between the two cars is still 65 kilometers. How many kilometers per hour does car B travel on average?
A、B两地相距785千米，甲、乙两辆汽车同时从A、B两地相对而行，已知甲车平均每小时行79千米，4.5小时后两车还相距65千米，乙车平均每小时行多少千米？
<gadget id="calculator">785 - 65</gadget>
<output>720</output>

<gadget id="calculator">720 / 4.5</gadget>
<output>160</output>

<gadget id="calculator">160 - 79</gadget>
<output>81</output>

<result>81</result>