Because 9 minutes =0. 15 hours.
16/x+0. 15 = 16/0.5x。
Multiply both sides by 0.5x, so.
8+0.075x= 16
Get x=320/3.
Test: When x=320/3, 0.5x is not equal to 0.
X=320/3 is the solution of the original equation.
A: The original planned speed is 320/3 kilometers per hour.