Step 1: Find the time taken for Alice to complete the whole journey
We know that their speed is constant throughout, so if Alice takes 35min to complete 1/2 of the journey, she will take 35 x 2 = 70 min to complete the whole journey.
Step 2: Find Ben’s speed
We know that Alice is 300m ahead of Ben at the halfway mark. As their speed is constant, we can expect that Alice will achieve yet another 300m lead when she reaches the end point. This means that she will be 300 x 2 = 600m ahead of Ben when she reaches the end point.
Since Alice reaches the end point 5 minutes before Ben, this means that Ben will take an extra 5 min to travel the 600m lead which Alice has. Therefore, we can find Ben’s speed by 600m / 5 min = 120m/min.
Step 3: Find the distance Ben travelled in the first 70 mins
120m/min x 70 min = 8400m
Step 4: Add up the total distance
8400 + 600 = 9000m