The average height of a group of 5 people is 70 inches. What is the height of the shortest person in the group?
1) If the shortest person left the group, the average height of the group would be 72,5 inches.
2) The ratio of height of the tallest person in the group to the height of the shortest person in the group is 5:4.
Proportions and sets
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- Java_85
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It's a little tricky question, IMO A is the answer. Here is why.
We've 5 people. the average for 4 of them is 72.5 and for 5 of them 70 ==> ((4*72.5)+(1*Shortest))/5=70 ==> using this equation shortest height can be calculated. ==> (1) is sufficient. ==> A or D
Using (2) we can't calculate the shortest person height because we just have a ratio==> A it is.
We've 5 people. the average for 4 of them is 72.5 and for 5 of them 70 ==> ((4*72.5)+(1*Shortest))/5=70 ==> using this equation shortest height can be calculated. ==> (1) is sufficient. ==> A or D
Using (2) we can't calculate the shortest person height because we just have a ratio==> A it is.
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We need to know the total weight of the group before and after a person is removed or that person goes out or another person comes into the group.Carloselopez wrote:The average height of a group of 5 people is 70 inches. What is the height of the shortest person in the group?
1) If the shortest person left the group, the average height of the group would be 72,5 inches.
2) The ratio of height of the tallest person in the group to the height of the shortest person in the group is 5:4.
Here statement 1 provides exactly the information we need, hence sufficient.
Statement gives a ratio between the tallest and shortest that cannot be used to find who is the shortest, because it relative to only 2 of them.
A
You can, for example never foretell what any one man will do, but you can say with precision what an average number will be up to!
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Target question: What is the height of the shortest person in the group?Carloselopez wrote:The average height of a group of 5 people is 70 inches. What is the height of the shortest person in the group?
1) If the shortest person left the group, the average height of the group would be 72.5 inches.
2) The ratio of height of the tallest person in the group to the height of the shortest person in the group is 5:4.
Given: The average height of a group of 5 people is 70 inches.
So, the sum of all 5 heights = (5)(70) = 350 inches
Statement 1: If the shortest person left the group, the average height of the group would be 72.5 inches
If the average height of 4 people is 72.5 inches, then the sum of the 4 heights = (4)(72.5) = 290 inches
The total height went from 350 inches to 290 inches (a 60-inch difference), so the shortest person in the group must be 60 inches tall
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: The ratio of height of the tallest person in the group to the height of the shortest person in the group is 5:4
As vinay1983 and Java_85 noted, this statement is not sufficient. To show this, consider these two conflicting cases:
Case a: the heights are {60, 71, 72, 72, 75} in which case the shortest person in the group is 60 inches tall
Case b: the heights are {64, 68, 68, 70, 80} in which case the shortest person in the group is 64 inches tall
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT
Answer = A
Cheers,
Brent
Dear Brent/All,
Sorry if this is a silly question-what if the question statement also mentioned that the heights were in Arithmetic progression or progression .Can statement 2 still not be used sufficiently ?It can be,am i correct?
Regards,[/list][/quote]
Sorry if this is a silly question-what if the question statement also mentioned that the heights were in Arithmetic progression or progression .Can statement 2 still not be used sufficiently ?It can be,am i correct?
Regards,[/list][/quote]
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No, that condition would not change things for statement 2. Consider these two cases:s.vishnu wrote:Dear Brent/All,
Sorry if this is a silly question-what if the question statement also mentioned that the heights were in Arithmetic progression or progression .Can statement 2 still not be used sufficiently ?It can be,am i correct?
Regards,
Case a: the heights are {60, 63.75, 67.5, 71.25, 75} in which case the shortest person in the group is 60 inches tall
Case b: the heights are {64, 68, 72, 76, 80} in which case the shortest person in the group is 64 inches tall
The same would apply to a geometric progression.
Cheers,
Brent