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by vishal chugh » Fri Nov 18, 2011 11:55 pm
if a/b= 1/3; b/c = 2; c/d= 1/2; d/e= 3; e/f=1/4; f/g= 1/6, then what is the value of the expression
abc/def ?
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by shankar.ashwin » Sat Nov 19, 2011 12:30 am
c/d * d/e = 1/2 * 3

Therefore, c/e = 3/2

b/c * c/d = 2*1/2 = 1

Therefore, b/d = 1

Multiplying we have bc/de = 3/2

We need to find a/f ,

Now, a/b * b/c * c/d * d/e * e/f = a/f = 1/3 * 2 * 1/2 * 3 * 1/4 = 1/4

Therefore abc/def = 3/2 * 1/4 = 3/8 IMO
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by pemdas » Sat Nov 19, 2011 12:38 am
del.
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by LalaB » Sat Nov 19, 2011 1:39 am
vishal chugh wrote:if a/b= 1/3; b/c = 2; c/d= 1/2; d/e= 3; e/f=1/4; f/g= 1/6, then what is the value of the expression
abc/def ?
need to find (a/f)*(b/d)*(c/e)

b/c = 2; c/d= 1/2 then (b/c) *(c/d)=2*1/2 b/d=1
c/d= 1/2; d/e= 3 then (c/d)*(d/e)=1/2*3 c/e=3/2

if u multiply all expressions- a/b= 1/3; b/c = 2; c/d= 1/2; d/e= 3; e/f=1/4; f/g= 1/6, u will find that all of them can be canceled out except a and q .so, we have got a/q=1/4*1/6=1/24
since q=6f then a/6f=1/24 a/f=1/4

so, now we have (a/f)*(b/d)*(c/e) =1/4*1*3/2=3/8

3/8 is the answ
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by GMATGuruNY » Sat Nov 19, 2011 4:50 am
vishal chugh wrote:if a/b= 1/3; b/c = 2; c/d= 1/2; d/e= 3; e/f=1/4; f/g= 1/6, then what is the value of the expression
abc/def ?
Let a=2.
Since a/b = 1/3, b=6.
Since b/c = 2, c=3.
Since c/d = 1/2, d=6.
Since d/e = 3, e=2.
Since e/f = 1/4, f=8.
abc/def = (2*6*3)/(6*2*8) = 3/8.

Strange problem: Why are we told that f/g = 1/6?
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by pemdas » Sat Nov 19, 2011 10:54 am
nice question Mitch, i think here's the clue re "f/g=1/6"
a/b * b/c * c/d * d/e * e/f * f/g = af/g= 1/24 and g=24*af <> considering f=g/6 we rewrite g=24*a(g/6) OR a=1/4 (after canceling 'g' on both sides)
Now a=1/4 and b=(1/4)*3=3/4; c=3/8; d=3/4; e=3/12; f=1 (possibly we are done here)
1/4 * 3/4 * 3/8 {divided by} 3/4 * 3/12 * 1 = 9/(16*8) * (4*12)/9 = 3/8
vishal chugh wrote:if a/b= 1/3; b/c = 2; c/d= 1/2; d/e= 3; e/f=1/4; f/g= 1/6, then what is the value of the expression
abc/def ?
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by vishal chugh » Sun Nov 20, 2011 7:35 pm
we are told f/g just to make the confuse n that we need to use f/g for getting solution. once you use the factor f/g, you r surely gonna waste lot of your time
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