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Re: what is the value of b? [#permalink]
09 Nov 2011, 08:41

1

This post received KUDOS

a and b are not integers here.

consider this:

Now for every value of a, there is a different value of b. Say, a = 1, then 4^b = 12 and b = 1.79 approx a = 2, then 4^b = 4 and b = 1 a = 3, then 4^b = 36/27 and b = 0.2 approx

Re: what is the value of b? [#permalink]
04 Feb 2012, 14:50

Expert's post

2

This post was BOOKMARKED

amit2k9 wrote:

straight B. 36 = 2 ^2 * 3^2

If 3^a*4^b = c, what is the value of b?

Note that we are not told that the variables are integers only.

(1) 5^a = 25 --> a=2, but we can not get the values of b. Not sufficient.

(2) c = 36 --> 3^a*4^b = c: it's tempting to write 3^2*4^1=36 and say that b=1 but again we are not told that the variables are integers only. So, for example it can be that 3^a=36 for some non-integer a and b=0, making 4^b equal to 1 --> 3^a*4^b =36*1=36. Not sufficient.

(1)+(2) As a=2 and c = 36 then 9*4^b=36 --> b=1. Sufficient.

Re: If 3^a * 4^b = c, what is the value of b? (1) 5^a = 25 (2) c [#permalink]
30 Sep 2014, 22:42

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