Six numbers a, b, c, d, e, f are such that a.b = 1, b.c =1/2, c.d = 6, d.e = 2, e.f =1/2. What is the value of (a.d : b.e : c.f) ?
A) 72 : 1 : 9
B) 8 : 9 : 9
C) 24 : 2 : 3
D) 6 : 1 : 9
E) 4 : 3 : 27
Six numbers
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- shashank.ism
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You could set up all kinds of crazy ratios, but almost certainly the quickest/easiest way to solve is to pick numbers.shashank.ism wrote:Six numbers a, b, c, d, e, f are such that a.b = 1, b.c =1/2, c.d = 6, d.e = 2, e.f =1/2. What is the value of (a.d : b.e : c.f) ?
A) 72 : 1 : 9
B) 8 : 9 : 9
C) 24 : 2 : 3
D) 6 : 1 : 9
E) 4 : 3 : 27
a*b = 1, so let's let:
a=1
b=1
Now working our way across:
1*c = 1/2
c = 1/2
(1/2)*d = 6
d = 12
12*e = 2
e = 1/6
(1/6)*f = 1/2
f = 3
Plugging our numbers into the question:
a*d = 12
b*e = 1/6
c*f = 3/2
Multiplying all three terms by 6 to eliminate fractions:
a*d : b*e : c*f = 72 : 1 : 9
Choose (A).
Here's the takeaway:
When you're given rules for how the variables behave, but no actual values, picking numbers that follow the rules is a great way to attack the question.
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- shashank.ism
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Yeah the OA is A.
Let f = 1, then finding values subsequently,
e = 1/2, d = 4, c =3/2 , b = 1/3, a = 3
Value of ad : be : cf = 72 : 1 : 9
Let f = 1, then finding values subsequently,
e = 1/2, d = 4, c =3/2 , b = 1/3, a = 3
Value of ad : be : cf = 72 : 1 : 9
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www.dictionary.webmaggu.com - A compact free online dictionary with images.
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