-gre.qu.10 quantity on 2 means

[karush]

posted a screenshot because I think the wording is awkward and I think it is easy to setup it up wrong

so to begin with we have a and b being list of added numbers
$\dfrac{a}{100}=23$ and $\dfrac{a+b}{150}=27$

so now what?

 

[kaliprasad]

we have sum of 100 measurements = 2300

sum of 50 additional measurements = 27 * 50 = 1350

total sum = 2300 + 1350 = 2650

so arithmetic mean = $\frac{3650}{150} = \frac{73}{3}$

so B is bigger

for a short cut 25 is mean of 23 and 27

more elements(100) have mean 23 and less (50) elements have 27 so arithmetic mean < 25

 

[karush]

mahalo i probably would of missed it