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4^12 and 5^23

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4^12 and 5^23

by sanju09 » Thu Aug 26, 2010 8:55 pm
How many digits does the product of 4^12 and 5^23 contain?
A. 12
B. 13
C. 23
D. 24
E. 35


[spoiler]Source: https://gmat-math.blocked/2010/02/4gmat[/spoiler]
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by 4GMAT_Mumbai » Thu Aug 26, 2010 9:05 pm
Hi,

Let x = 4^12 * 5^23

x = (2 ^ 24) * (5 ^ 23)

x = (10 ^ 23) times 2

10 ^ 23 has 24 digits. Multiplying it by 2 does not increase the # of digits.

My take is D ... OA pls ...
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by sanju09 » Thu Aug 26, 2010 9:31 pm
4GMAT_Mumbai wrote:Hi,

Let x = 4^12 * 5^23

x = (2 ^ 24) * (5 ^ 23)

x = (10 ^ 23) times 2

10 ^ 23 has 24 digits. Multiplying it by 2 does not increase the # of digits.

My take is D ... OA pls ...
click on 'Thanks' OA's ;-D
The mind is everything. What you think you become. -Lord Buddha



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