According to police, 15-year-old Pradip Tamang of Chandragiri-18 was seriously injured in the accident.
Tamang passed away while being treated at the Maharajgunj-based Teaching Hospital, police said.
Sabin Tamang, 13, who also got injured the mishap, is receiving treatment at Neelam Hospital in Balambu.
Police have impounded the truck, while driver is at large.
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