1. **Stating the problem:** We have 60 vehicles in total. 28 are cars and the rest are vans. Among the cars, 7 are second-hand, and among the vans, 5 are new. We need to find the value of $D$ (the number of new cars) and the total number of second-hand vehicles. 2. **Frequency tree setup:** - Total vehicles: 60 - Cars: 28 - Vans: $60 - 28 = 32$ 3. **Cars branch:** - Second-hand cars: 7 - New cars: $D$ - Since total cars = 28, we have: $$7 + D = 28$$ $$D = 28 - 7 = 21$$ 4. **Vans branch:** - New vans: 5 - Second-hand vans: Let this be $x$ - Total vans = 32, so: $$x + 5 = 32$$ $$x = 32 - 5 = 27$$ 5. **Total second-hand vehicles:** - Second-hand cars: 7 - Second-hand vans: 27 - Total second-hand vehicles: $$7 + 27 = 34$$ **Final answers:** - $D = 21$ - Total second-hand vehicles = 34