organized counting: What percentage watch news at 1200 hours

[cr7]

hey
i was wondering if someone could help me with this question:
A survey of 1000 people was conducted by a local new station and produced the following information:
40% watch the news at 12 00
60% watch the news at 18 00
50% watch the news at 23 00
25% watch the news at 12 00 and 18 00
20% watch the news at 12 00 and 23 00
20% watch the news at 18 00 and 23 00
10 % watch all three broadcasts

What percentage watch the news at 12 00 and 18 00 hours but not 23 00 hours?


If someone could solve this problem it would be greatly appreciated, or even if they could show a detailed question that is similar to this.

Thankz

 

[galactus]

What part of the Venn includes both 1200 and 1800 hours, but not 2300 hours?.