Of 10 senior citizens surveyed, 60% like chocolate icecream and 70% like strawberry icecream. What percentage of people like both chocolate and strawberry?

I saw this question the other day and thought that the people must like more than one flavour and so that 60% would be the appropriate answer. My classmate got 30%. Whose right and how?
Thanks for your help.😀

1 Answer
BillytheKid
Nov 13, 2017

Neither of you, and both of you in a way...

Explanation:

60% for Chocolate,
70% for Strawberry.

So, 6 of 10 like Chocolate;
7 out of 10 like Strawberry BUT: they might not be the same persons.

It might be that all 6 who like Chocolate might also like Strawberry, so the answer will be 60%, but you don't know for sure.

All you know is that there are 4 people (40%) of the 10 who don't like Chocolate, so there must be at least 3 people (30%) who like both flavours....

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