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by galaxian » Sat Jul 02, 2011 5:25 pm
This is not a GMAT Qs at all but a CAT one.
You can easily calculate the reminder in this case if you know the negative reminder concept.
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by winniethepooh » Sat Jul 02, 2011 7:28 pm
The answer is 25?
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by MBA.Aspirant » Sat Jul 02, 2011 8:51 pm
Someone has posted a similar answer so it might be right. Please explain
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by Frankenstein » Sun Jul 03, 2011 6:14 am
Hi,
3^64 = 3.3^63 = 3.(3^3)^21 = 3.(27)^21
=3.(28-1)^21
(28-1)^21 when expanded(binomial expansion) gives 28^21 + 21C1.(28^20)(-1)+...+28C27.(28).(-1)^20+(-1)^21
So, every term of this sum is a multiple of 28 except the last term i.e. (-1)^21 which is (-1)
So, 3(28-1)^21 = 3(28*p - 1) = 3.28p - 3 = 28(3p-1)+25
So, remainder is 25
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