2025 AISS PRELIMS P2 Q4

Jennie travels from Town (A) to Town (B) at a speed of (x) km/h. The journey takes 1 hour. She then spends 30 minutes having her lunch in Town (B), before setting off to Town (C), which takes (x) minutes at ((x-20)) km/h. The total distance of the journey is 120 km.

1. Show that (x^2+40x-7200=0).[3]
2. Solve the equation (x^2+40x-7200=0). Given your solutions correct to 2 decimal places.[3]
3. Explain why one of the solutions in part (b) must be rejected.[1]
4. Calculate the difference between the times Jennie spent driving from Town (A) to Town (B) and from Town (B) to Town (C). Give your answer in minutes and seconds, correct to the nearest second.[1]
5. Calculate Jennie’s average speed for the entire journey.[3]