The solution is X= 18.

2. The price of a garment after one-fifth reduction is 2 1.6 yuan, so the initial price of this garment is 2 1.6*5= 108.

The final price of clothes is (108-21.6) * 0.9 = 77.76.

3 . 0 . 6+2/5+0.5 = 1.5 & lt； 1 4/5, so Xiaojie's actual operation time did not exceed the planned time.