A plainclothes policeman got on the bus and suddenly found a thief walking in the opposite direction. After 10 seconds, he got off the bus to chase the thief. It is known that the speed of the criminal policeman is twice as fast as that of the thief and slower than that of a car (4/ 5). So, how many seconds does it take for the criminal to catch up with the thief?
一名便衣刑警坐上了公共汽车，忽然发现一个小偷向相反的方向步行，10秒钟后他下车去追小偷，己知刑警的速度比小偷快一倍，比汽车的速度慢(4/5)．那么，这名刑警追上小偷需要多少秒．
<result>110</result>