The speed of a motorcycle is 45 km/h, the speed of a car is twice the speed of the motorcycle, and the speed of an airplane is 30 km/h less than 9 times the speed of the car. Find the speed of the plane.
一辆摩托车的速度是45千米/时，一辆小汽车的速度是这辆摩托车的2倍，一架飞机的速度比这辆小汽车的9倍少30千米/时．求这架飞机的速度．
<gadget id="calculator">45 * 2 * 9</gadget>
<output>810</output>

<gadget id="calculator">810 - 30</gadget>
<output>780</output>

<result>780</result>