In a certain school, the pupils have to study Maths, Science, or Geography. Each pupil must at least study one subject. Among a group of 40 pupils, 20 are studying Maths, 22 are studying Science, and 28 are studying Geography. 12 are studing both Maths and Science, 14 are studying both Science and Geography, and 15 are studying both Maths and Geography. How many pupils are studing all 3 subjects?
The answer is 11 but I need the workings CLEARLY please. Best to include explanations beside each step as well. Please try to respond in 150 mins time from the time of this posting.
2006-09-14
01:30:58
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5 answers
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asked by
miss flames
1