9. (12 points) $A$ and $B$ are 30 centimeters apart. Two strings, Jia and Yi, are pulled by toy cars starting from $A$ and $B$ respectively, moving towards each other. Jia is 151 centimeters long and moves at a speed of 2 centimeters per second; Yi is 187 centimeters long and moves at a speed of 3 centimeters per second. If the ends of the two strings are lit at the same time when they start, Jia burns at a rate of 1 centimeter per second, and Yi burns at a rate of 2 centimeters per second. The time it takes for the two strings to meet and completely pass each other is $\qquad$ seconds.
【Answer】Solution: $30 \div(2+3)=6$ (seconds), $(151+187)-(1+2) \times 6=320$ (cm), $320 \div(2+3+1+2)=320 \div 8=40$ (seconds),

Answer: It takes 40 seconds for the two ropes to completely separate after they meet.