500 ds test6 #21

dunkin77 wrote:Hi,

I thought the answer is C) but correct answer is E). I thought if we can varify that Z is positive by (1), r ans k are also positive in order by (2)....Can anyone please explain?


Are the numbers k/4,z/3 and r/2 in increasing order?
(1) 3 < z < 4
(2) r < z < k

with first statemnet we can say that z/3 is > 1 .. bcoz z is > 3 .. but it does not say anything abt r and k so insufficient ..


with the sceond statemnet we do not know the value of r,z,k .. nor do we know wether they are positive or negative so insufficinet

when we combine them... we know that z > 3 and that k is > z .. but we styill wont be able to say wether k/4 > or < than z/3 ..for eg .. let z = 3.1 and let k=3.2 which is > z but in this case z/3 is > k.4 ... now consider z = 3.1 and k = 10 (k > z ) .. in this case k/4 > z/3 so we wont get a defnite answer ... also r can be negative or postive .. so combinig the 2 statments will not help either so answer is E ....

you are right.

even though Z, K are positive, r can be positive or negative. So, E) is right.