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If a = 2/3^7 + 2/3^8 + 2/3^9 +2^2/3^9, then what is the value of a?

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Joined: 02 Sep 2009
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If a = 2/3^7 + 2/3^8 + 2/3^9 +2^2/3^9, then what is the value of a?  [#permalink]

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11 Jan 2018, 21:48
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15% (low)

Question Stats:

93% (01:20) correct 7% (00:56) wrong based on 42 sessions

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If $$a = \frac{2}{3^7} + \frac{2}{3^8} + \frac{2}{3^9} + \frac{2^2}{3^9}$$, then what is the value of a?

A. 32/3^33

B. 10/3^8

C. 10/3^6

D. 10/3^2

E. 3

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Re: If a = 2/3^7 + 2/3^8 + 2/3^9 +2^2/3^9, then what is the value of a?  [#permalink]

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12 Jan 2018, 00:52

a=2/3^7 + 2/3^8 + 2/3^9 + 2/3^9

a= 2/3^7 *(1+1/3+1/9+2/9)

a=2/3^7 * (15/9)

a= 30/3^9

a= 10/3^8
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Re: If a = 2/3^7 + 2/3^8 + 2/3^9 +2^2/3^9, then what is the value of a?  [#permalink]

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12 Jan 2018, 05:32
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a= $$\frac{2}{3^7}$$+$$\frac{2}{3^8}$$+$$\frac{2}{3^9}$$+$$\frac{2^2}{3^9}$$

= $$\frac{2}{3^7}$$[1+$$\frac{1}{3}$$+$$\frac{1}{9}$$+$$\frac{2}{9}$$]

= $$\frac{2}{3^7}$$*[$$\frac{15}{9}$$]

= $$\frac{30}{3^9}$$

= $$\frac{10}{3^8}$$

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Re: If a = 2/3^7 + 2/3^8 + 2/3^9 +2^2/3^9, then what is the value of a? &nbs [#permalink] 12 Jan 2018, 05:32
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