The World Health Organization (WHO) has produced a comprehensive set of growth standards for children. These standards are based on studies of children living in 6 nations on 5 continents under optimal conditions with respect to health and nutrition. The table displays the percentil distribution of height, in centimeters, at 3month intervals, for boys ages 2 through 5 according to the WHO model. In a model population  a large population of boys ages 2 through 5 that conforms to the WHO growth standards  for n = 3, 15, 50, 85, and 97, nth percentile in height for a given age is the unique height among boys of that age that is greater than or equal to n percent, and less than or equal to (100 n) percent, of heights of boys of that age.
This topic has expert replies
 Anaira Mitch
 Master  Next Rank: 500 Posts
 Posts: 235
 Joined: 26 Oct 2016
 Thanked: 3 times
 Followed by:5 members
 DavidG@VeritasPrep
 Legendary Member
 Posts: 2666
 Joined: 14 Jan 2015
 Location: Boston, MA
 Thanked: 1153 times
 Followed by:125 members
 GMAT Score:770
Consider an individual boy from a model population. Suppose that from age 2 through age 5, this boy's weight is at the 50th percentile for his height and his height is at the 50th percentile for his age. Which one of the following statements must be true of the boy at age 5 years 0 months?
A) His age is at the 50th percentile for his height.
B) His weight is at the 50th percentile for his age.
C) His height is at the 50th percentile for his weight.
D) His weight is approximately 150% of his weight at age 2 years 0 months.
E) His weight is approximately 200% of his weight at age 2 years 0 months.
If this boy is 50th percentile height for his age when he's five, we can see that he'll be 110 cm. If his weight is 50th percentile for his height, then we can use the weightforheight graph and find the weight that corresponds to 110 for the yellow line. It looks to be about 18kg.
If this boy is 50th percentile height for his age when he's two, we can see that he'll be 87 cm. If his weight is 50th percentile for his height, then we can use the weightforheight graph and find the weight that corresponds to 87 for the yellow line. It looks to be about 12kg.
18 is 150% of 12. (18/12) * 100 =150. So the answer is D.
A) His age is at the 50th percentile for his height.
B) His weight is at the 50th percentile for his age.
C) His height is at the 50th percentile for his weight.
D) His weight is approximately 150% of his weight at age 2 years 0 months.
E) His weight is approximately 200% of his weight at age 2 years 0 months.
If this boy is 50th percentile height for his age when he's five, we can see that he'll be 110 cm. If his weight is 50th percentile for his height, then we can use the weightforheight graph and find the weight that corresponds to 110 for the yellow line. It looks to be about 18kg.
If this boy is 50th percentile height for his age when he's two, we can see that he'll be 87 cm. If his weight is 50th percentile for his height, then we can use the weightforheight graph and find the weight that corresponds to 87 for the yellow line. It looks to be about 12kg.
18 is 150% of 12. (18/12) * 100 =150. So the answer is D.

 Legendary Member
 Posts: 944
 Joined: 30 May 2012
 Thanked: 8 times
 Followed by:4 members
@ Dave: Why B is wrong in the first Qs ?
Last edited by RBBmba@2014 on Mon Sep 18, 2017 11:18 pm, edited 1 time in total.

 Legendary Member
 Posts: 944
 Joined: 30 May 2012
 Thanked: 8 times
 Followed by:4 members