Thursday, December 30, 2010

Percentage P6

In a primary school, 50 pupils were surveyed on the pets they liked. 80% of the pupils liked dogs, 50% of them liked birds and 34% of them liked rabbits. The survey results were that 1 out of every 5 pupils did not like any of the animals. What is the least number of pupils who liked all 3 types of animals. [Ans : 2]


1/5 x 50 =10 -- did not like pets


100% --> 50

80% --> 80/100 x 50 = 40 -- like dogs

50% --> 50/100 x 50 = 25 -- like birds

34% --> 34/100 x 50 = 17 -- like rabbits

25 + 17 - 40 = 2 pupils   Least overlap between those who like birds and rabbits

The least number of pupils who liked all 3 types of animals is 2.

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