Value of w

tanyajoseph · Posted: Mon Sep 03, 2007 12:28 pm Post subject: Value of w

If r,sand w are positive nos such that w = 60r+80s and r+s=1, is w <70?

1) r>0.5
2)r>s

Neo2000 · Posted: Mon Sep 03, 2007 8:08 pm Post subject:

Lets say r = 0.5 so s= 0.5
Then w = 70

But r>0.5 which means as r increases, s decreases which means w will always <70 (try with r = 0.6)

So A is sufficient

From 2 we get nothing

Hence A

abkhan · Posted: Mon Sep 03, 2007 10:50 pm Post subject:

right A should be the answer

Guest · Guest

I think the Answer should be "C"
Each alone is sufficient

Explanation for statement 1 i.e r>0.5 is ok but I would explain it as follows:
given w=60r+80s
if r=0.5 ,s =0.5 then w =70
however as r increases 60r increases & at the same time
s decreases causing 80s to decrease which would always be more
than the increase in 60r hence for every increase in 60r the
corresponding decrease in 80s would be more
Therefore w<70 for r.0.5

however the second statement i.e. r>s also implies the same

here is the explanation:

given that r+s =1 & both are positive nos

hence If r > s then it has to be greater than 0.5 otherwise it is not possible for r+s =1

Hence the statement r>s indirectly means that r>0.5 which is the
first statement, hence statement 2 is also sufficient, so Answer should be
"C".

agps · Posted: Tue Sep 04, 2007 12:25 am Post subject:

you mean D. either one is enough is D.
and I agree with your explanation.

Guest · Guest

Sorry, I meant the answer should be "D" Each is sufficient alone.

number · Guest