1000DS section 8 #25

[rookiez]

How come OA is C
25. How many integers n are there such that
r < n < s?
(1) s – r = 5
(2) r and s are not integers.

IMO A

[shibal]

if r and s are integers, ou'd know the answer easily, however it doesn't say in the stem that r and s are both integers....
therefore A wouldn't be right...
wth stmt 2 it gives us the missing info, which enables us to get the answer....

[rookiez]

yes its not mentioned in the question whether r/s are integers or fractions...but stmt 1 still should suffice...
from stmt 1 s - r = 5 which implies
i. conside r as a fraction r=3/4; hence s should be = 23/4 to satisfy s-r=5...and terefore we still can count how many integer 'n' are in between these 2 s & r
ii. s=17, r=12....hence 17-12=5...and hence we know how many integers are between these 2

still A

[PumaJr]

yes its not mentioned in the question whether r/s are integers or fractions...but stmt 1 still should suffice...
from stmt 1 s - r = 5 which implies
i. conside r as a fraction r=3/4; hence s should be = 23/4 to satisfy s-r=5...and terefore we still can count how many integer 'n' are in between these 2 s & r
ii. s=17, r=12....hence 17-12=5...and hence we know how many integers are between these 2

still A

If r and s could either be fractions or integers, then n could equal 5 if r and s are fractions or 4 if r and s are integers. Insufficient. You need the information given in ii. to lock down which case it is.