Daniel was 4km ahead of Ethan when Ethan reached the halfway mark.

Since Daniel's speed was 24km/h, time he took to travel this 4km = 4km ÷ 24km/h
= 1/6 h = 10 minutes

Since Daniel took 10 minutes to travel this 4 km, this means that he actually reached the halfway mark 10 minutes before Ethan did.

So Ethan takes 10 more minutes to reach the halfway mark than Daniel.

So for the whole journey, which is twice of that distance,

Ethan will take 10min x 2 = 20 more minutes to finish it than Daniel


11.50 + 00.20 = 11.70 = 12.10

So Ethan will finish at 12.10pm