knewton red cross

[pradeepkaushal9518]

In a certain year, the Red Cross raised a total of $0.9 billion from individual donations over $1000. Of this $0.9 billion, 16.8% was paid by the 5 highest-contributing individuals, and the balance was paid by the remaining 312 contributors. Was Mr. X among the 5 highest-contributing individuals?

12.1% of this $0.9 billion was paid by the 3 highest-contributing individuals, each of which paid more than Mr. X.
Mr. X paid 1.9% of the $0.9 billion.

[Maciek]

Hello,

IMO E
what is the OA?

total amount - $0.9 billion
the 5 highest-contributing individuals - 16.8%*$0.9 billion
312 remaining contributors - (100% - 16.8%)*$0.9 billion

We need to know if Mr. X among the 5 highest-contributing individuals.

(1) the 3 highest-contributing individuals - 12.1%*$0.9 billion

let us plugin numbers:
the 1st highest-contributing individual paid 6%*$0.9 billion
the 2nd highest-contributing individual paid 3.1%*$0.9 billion
the 3rd highest-contributing individual paid 3.0%*$0.9 billion

the 4th highest-contributing individual paid 2.9%*$0.9 billion
the 5th highest-contributing individual paid 1.8%*$0.9 billion

It is possible that
Mr. X paid 1.8%*$0.9 billion and was the 5th highest-contributing individual.
and it is also possible that
Mr. X paid 1%*$0.9 billion and was not among the 5 highest-contributing individuals.
so this statement alone is INSUFFICIENT

(2) Mr. X paid 1.9% of the $0.9 billion

let us plugin numbers:
the 1st highest-contributing individual paid 6%*$0.9 billion
the 2nd highest-contributing individual paid 3.0%*$0.9 billion
the 3rd highest-contributing individual paid 3.0%*$0.9 billion

it is possible that
the 4th highest-contributing individual paid 2.9%*$0.9 billion
the 5th highest-contributing individual paid 1.9%*$0.9 billion and it was Mr. X
and it is also possible that
the 4th highest-contributing individual paid 2.5%*$0.9 billion
the 5th highest-contributing individual paid 2.3%*$0.9 billion and Mr. X was not among the 5 highest-contributing individuals.

[spoiler]so we don't have enough information to answer the question
IMO E[/spoiler]

hope it helps!