**
John rides his bike from his home to a park at an average speed of 15 km/h. The journey takes him 24 minutes. On his way back, he takes a different route that is 2 km longer and his average speed decreases to 10 km/h due to rough terrain. How long, in minutes, does it take for John to return home?

** Let's think step by step and output the final answer within \boxed{}.
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