Answer: 1:30 (one hour and thirty minutes)
Step-by-step explanation:
If he jogs 12 km in an hour, and he wants to jog 18 km, you divide 12 km from when he jogged for and hour by 2 and get 6. Add 12 km to 6 km, and get 18 km in one hour and thirty minutes. So, basically 6 km every 30 minutes.
