In the sequence of positive numbers X1, X2, X3....what is the value of X1?
(1) xi = (xi-1)/2 for all integers i>1
(2) x5 = x4/(x4+1)
source is GMAC practice test #1, answer is C
what am I missing?
sequence/data suff
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its CBILL wrote:In the sequence of positive numbers X1, X2, X3....what is the value of X1?
(1) xi = (xi-1)/2 for all integers i>1
(2) x5 = x4/(x4+1)
source is GMAC practice test #1, answer is C
what am I missing?
here it goes
statement 1. xi = (xi-1)/2 for all integers i>1
tells us nothing ............insufficient
statement 2. x5 = x4/(x4+1)
again nothing ..............insuffcient
combining together...
we know
xi = (xi-1)/2 thus X5 will be X4/2 ( Xi-1/2)..........................a
but statement 2 says X5 = x4/(x4+1).................................b
equate a and b
X4/2 = x4/(x4+1)
thus X4 = 1
now we can use this to find X1
thus C is the answer..
do let me know if u have any doubts...