Question

In a certain class 40percent of the students take coffee, 40percent take tea and 50percent take milk. 10percent take all the three. Also 20 percent take coffee and tea, 20percent take tea and milk and 20percent take coffee and milk. 10 students do not take any of the three.What percentage of students take exactly two of the three drinks?

Answer 1

Answer:

60 percent of the students take exactly two of the three drinks.

Answer 2

Answer:

Given

40percent of the students take coffee, n(c) =40

40percent take tea, n(t) =40

50percent take milk, n(m) = 50

10percent take all the three n(c∩ t∩m) =10

20 percent take coffee and tea, n(c∩ t) =20

20percent take tea and milk, n(t∩ m) = 20

20percent take coffee and milk, n(c∩ m) =20

10 students do not take any of the three, n(c∪t∪m) ' =10

percentage of students take exactly two of the three drinks,

[n(c∩ t)- n(c∩ t∩ m) ] +[n(t∩ m) -n(c∩ t∩ m)] + [n(c∩ m)-n(c∩ t∩ m)]

=(20-10)+(20-10)+(20-10)

=10+10+10

=30

Therefore 30 percentage of students take exactly two of the three drinks