jatinet Posted May 17, 2005 Share Posted May 17, 2005 The average height for a group of students is 164. If the average height of the female students is 160, is the number of the female greater than the number of the males? 1) The average of the males is 170 2) There are 20 female students. Quote Link to comment Share on other sites More sharing options...
dsaqwert Posted May 17, 2005 Share Posted May 17, 2005 only first one is enough cause if they are equal, then the total average should be 165. but since it is smaller than 165, number of females should be larger than number of males Quote Link to comment Share on other sites More sharing options...
alex_cute Posted May 17, 2005 Share Posted May 17, 2005 dsaqwert, could you please explain further. My answer is A My approach: Females/x = 160, where x is the number of females -> females' height is 160x males/y= ?, where y is the number of males females+males/x+y=164 from statement 1: males/y=170 -> males' height=170y 160x+170y/x+y =164 160x+170y=164x+164y 4x=6y x=3/2 *y Consequently, x>y, i.e. number of females is bigger than that of males -> statement 1 is enough Statement 2 is not enough as we don't know the combined height or the average or the number of males. Quote Link to comment Share on other sites More sharing options...
rd_eastbay Posted May 17, 2005 Share Posted May 17, 2005 A it is. Quote Link to comment Share on other sites More sharing options...
Jeeves Posted May 17, 2005 Share Posted May 17, 2005 My ans is A similar approach to alex. dsaqwert could you explain your approach or if their is a shorter logic to get to the ans. Quote Link to comment Share on other sites More sharing options...
dsaqwert Posted May 17, 2005 Share Posted May 17, 2005 My ans is A similar approach to alex. dsaqwert could you explain your approach or if their is a shorter logic to get to the ans. ok, let;s make it more clear; assume number of boys and girls are equal, and knowing that the average of girls is 160 and the average of boys is 170, what overall average would you expect.... yes 165 ([160x + 170x]/2x=165) however the overall average is 164, in other words number of girls should be more than number of boys to ensure that the overall average is closer to the girls' average in other words (mathematically); x=number of girls y=number of boys 160x+170y=164(x+y) 6y=4x x=1.5y x>y Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.