Let's assume that the restaurant has 100 items on the menu.
- 60% of these items are main meals, which is 60/100 x 100 = 60 items.
- The remaining 40% of the items are starters, which is 40/100 x 100 = 40 items.
- 50% of the main meals are vegetarian, which is 50/100 x 60 = 30 items.
- 20% of the starters are vegetarian, which is 20/100 x 40 = 8 items.
Therefore, the total number of vegetarian items on the menu is 30 + 8 = 38 items.
The percentage of vegetarian items on the menu is 38/100 x 100 = 38%.
So, 38% of the items on the menu are vegetarian.