1. **Problem statement:**
Two vehicles start at the same time from towns A and B, 160 km apart, traveling towards each other. The lorry travels at 45 km/h from A to B, and the car travels at 75 km/h from B to A. They meet at town C.
2. **Formula and rules:**
When two objects move towards each other, the sum of distances they cover equals the total distance between them:
$$d_1 + d_2 = D$$
where $d_1$ and $d_2$ are distances traveled by the lorry and car respectively, and $D=160$ km.
Speed = Distance / Time, so Time = Distance / Speed.
Since they start at the same time and meet at the same time, their travel times are equal:
$$t = \frac{d_1}{45} = \frac{d_2}{75}$$
3. **Find the meeting time (a)(i):**
Let $t$ be the time in hours after 11:50 am when they meet.
From the total distance:
$$d_1 + d_2 = 160$$
Using $d_1 = 45t$ and $d_2 = 75t$:
$$45t + 75t = 160$$
$$120t = 160$$
$$t = \frac{160}{120} = \frac{4}{3} = 1.3333 \text{ hours}$$
Convert $1.3333$ hours to hours and minutes:
$$1.3333 \times 60 = 80 \text{ minutes}$$
So, they meet 1 hour 20 minutes after 11:50 am.
Meeting time = 11:50 am + 1 hour 20 minutes = 1:10 pm.
4. **Find distance from A to C (a)(ii):**
Distance from A to C is distance traveled by lorry:
$$d_1 = 45t = 45 \times \frac{4}{3} = 60 \text{ km}$$
5. **Find average speed of car from C to A (b):**
The car stops at C for 1 hour 40 minutes = $1 + \frac{40}{60} = 1.6667$ hours.
Time taken by lorry to travel from C to B:
Distance from C to B:
$$160 - 60 = 100 \text{ km}$$
Time:
$$t_{lorry} = \frac{100}{45} = 2.2222 \text{ hours}$$
Total time for lorry from A to B:
$$t_{total} = 1.3333 + 2.2222 = 3.5555 \text{ hours}$$
The car arrives at A at the same time as the lorry arrives at B.
Time car travels from B to C:
$$t = 1.3333 \text{ hours}$$
Stop time at C:
$$1.6667 \text{ hours}$$
Let $v$ be the average speed of car from C to A.
Distance from C to A:
$$60 \text{ km}$$
Time car travels from C to A:
$$t_{car} = \frac{60}{v}$$
Total time for car from B to A:
$$1.3333 + 1.6667 + \frac{60}{v} = 3.5555$$
Simplify:
$$3 + \frac{60}{v} = 3.5555$$
$$\frac{60}{v} = 0.5555$$
$$v = \frac{60}{0.5555} \approx 108 \text{ km/h}$$
**Final answers:**
- (a)(i) The vehicles met at **1:10 pm**.
- (a)(ii) Distance from A to C is **60 km**.
- (b) Average speed of car from C to A is approximately **108 km/h**.
Vehicles Meeting 1D704C
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