Wednesday, September 29, 2010

If p, q, r, and s are consecutive integers, with p

If p, q, r, and s are consecutive integers, with p '<' q '<' r '<' s, is pr '<' qs?

(1) pq '<' rs
(2) ps '<' qr








P'<'q'<'r'<'s
If they are consecutive
Then q = p+1 , r = p+2 and s = p+3
The question is pr '<'qs let plug in
Is p(p+2) '<' (p+1)(p+3) lets simplify
Is p^2 + 2p '<' P^2 +4p +3 --'>' -2p '<' 3 --'>' p'>'-1.5

So we can rephrase the question to --'>' is p '>'-1.5

(1) pq '<'rs
p(p+1) '<' (p+2)(p+3)
p^2 +p '<' p^2 +5p+6
-4p '<'6
p'>'-1.5 SUFFICIENT

(2) ps '<'qr
P(P+3) '<' (P+1)(P+2)
P^2+3P '<' P^2+3P+2
0 '<'2
This tells us nothing. Insufficient

Answer = A

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