ejager wrote:This problem is from MGMAT
4^a + 4^a+1 = 4^a+2 - 176
OA is a=2 but I don't understand the arithmetic please help
4^(a+2) - 4^(a+1) - 4^a = 176.
In other words:
176 = difference between 3 CONSECUTIVE POWERS OF 4.
List the powers of 4:
4, 16, 64, 256...
The next greatest power of 4 will be too great (over 1000).
Test the 3 greatest values in the list above:
256-64-16 = 176.
Success!
Since 4^a = 16, a=
2.
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