A nonprofit organization is planning to recruit volunteers for an upcoming community event. They have identified three key roles: Event Coordinator, Logistics Support, and Outreach Specialist. The organization aims to have a diverse group of volunteers, ensuring that at least 50% of the volunteers come from underrepresented communities. If they plan to recruit a total of 40 volunteers, how many volunteers must come from underrepresented communities to meet their diversity goal? Additionally, if the organization has already secured 10 volunteers from underrepresented communities, how many more do they need to recruit to meet their target?