Here's how we can infer his intelligence:
* Taking Care of His Family: Darry shoulders the responsibility of raising his younger brothers, Ponyboy and Sodapop, after their parents' death. He holds down a tough job and makes sacrifices to provide for them, showing a maturity and understanding beyond his years. This requires a high level of practical intelligence and emotional intelligence to manage finances, handle family conflicts, and provide for the needs of his brothers.
* Understanding Ponyboy: Darry often seems harsh towards Ponyboy, but his actions are driven by a desire to protect him and keep him safe. He understands that Ponyboy is a sensitive boy who needs guidance and discipline. This indicates a degree of emotional intelligence and empathy, key aspects of overall intelligence.
* Making Tough Decisions: Darry faces difficult choices, such as deciding whether to send Ponyboy to a reformatory after the fight at the drive-in. He weighs the consequences of his actions and chooses what he believes is best for his family, demonstrating a practical intelligence and the ability to think critically.
* Respect from Others: While the Greasers might not always be the most educated group, Darry earns respect from both his gang members and the Socs, suggesting that he commands a degree of authority and understanding that comes from intelligence.
In conclusion, Darry's intelligence in "The Outsiders" is mainly implied through his responsible behavior, his ability to care for his family, and his understanding of others. While not explicitly stated, his actions reveal a combination of practical, emotional, and social intelligence that makes him a strong and capable young man.