Bunuel wrote:
banksy wrote:
284. Each of 30 parents chose one of five days from Monday through Friday to attend parent-teacher conferences. Was at least one of the five days chosen by more than 10 parents?
(1) 15 parents chosen Monday or Tuesday.
(2) Each of the five days was chosen by at least 5 parents.
Each of 30 parents chose one of five days from Monday through Friday to attend parent-teacher conferences. Was at least one of the five days chosen by more than 10 parents?
(1) 15 parents chosen Monday or Tuesday --> we can have YES answer, (for example: 14-1-5-5-5) as well as NO answer, (for example: 10-5-5-5-5). Not sufficient.
(2) Each of the five days was chosen by at least 5 parents --> even if we distribute parents: 5-5-5-5-10, we still won't have any day which was chosen by more than 10 parents (minimizing # of parents who chose each of 4 days to maximize # of parents who chose the fifth day). Sufficient.
Answer: B.
Missed the word
more and got the wrong answer .
If it was " Was at least one of the five days chosen by at least 10 parents ?" then the answer could be E
Then
(1) 15 parents chosen Monday or Tuesday --> case 1: 10, 5 answer is yes ( showing Monday, Tuesday only )
--------------------------------------------------- -- case 2: 8,7 answer is no
2) Each of the five days was chosen by at least 5 parents -->
case1: 6 6 6 6 6 ,Answer No
case2: 10 5 5 5 5,Answer Yes
1+2
10 5 5 5 5, Answer Yes
8 7 5 5 5, Answer No
Still not sufficient
with the word " more than 10 parents " then of course the answer is B
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