According to the diagram we have:
- Total number of watches = 1000,
- Imported watches = 600,
- Imported damaged = 30,
- Local not damaged = 320.
Solution
i) Set of watches which are local and not damaged is the region within the rectangle but outside of circles.
ii) The missing number is the number of the total of damaged watches. We obtain it as follows:
- 1000 - 600 - 320 = 80, the number of damaged local watches,
Add 30 to this - the number of damaged imported watches:
- 80 + 30 = 110, this is the missing number of total damaged watches.
iii) The number of watches with no damage:
or
- Imported not damaged + local not damaged =
iv) If all damaged watches are imported then the second circle moves inside the first one.
The numbers become:
- The first circle, imported watches = 600,
- Inside circle, damaged watches = 110,
- The total number on the rectangle = 1000,
The number outside of circles but inside the rectangle, which is the number of local watches:
- Total - imported =
- 1000 - 600 =
- 400
