Question 1
Nine guests arrive at a party by car. The car park has three columns, each holding three cars one behind another. On arrival, a car must occupy the first available place in one column. A car can leave only if no other car is behind it in that column. In the example, E can leave immediately, but D must wait for F to move.

The cars arrive in the order A, B, C, D, E, F, G, H, I. They want to leave in the order G, D, F, I, H, C, B, A, E. Which arrangement meets both requirements?


The cars arrive in the order A, B, C, D, E, F, G, H, I. They want to leave in the order G, D, F, I, H, C, B, A, E. Which arrangement meets both requirements?





















