Towns a and b are 420 apart two Lorrie departed from a same travelling towards b lorry x travelled at an average speed of 15km/h less Yand 1hour and24hourslater

Question

Calculator the average speed

Answer 1

To calculate the average speed, we need to find the total time it took for both lorries to reach town B.

Let's assume the average speed of lorry Y is 'v' km/h.

Lorry Y departed 1 hour and 24 minutes later than lorry X.
So, the time taken by lorry X to reach town B = d/s = 420/v + 1 (1 hour travel time)

Lorry Y departed 24 hours later than lorry X.
So, the time taken by lorry Y to reach town B = d/s = 420/v

The total time taken for both lorries to reach town B = 420/v + 1 + 420/v

Now, we can find the average speed:
Average speed = total distance / total time
= 420 / (420/v + 1 + 420/v)
= 420v / (840 + v + 840)
= 420v / (1680 + v)

Therefore, the average speed is 420v / (1680 + v) km/h.