Three numbers are formed by taking three successive powers of 4. The sum of these three numb

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18 Dec 2009 Power of 4

Three numbers are formed by taking three successive powers of 4. The sum of these three numbers is 21504.
What is the greatest power raised

OPtion

1) 10
2) 8
3) 9
4) 6
5) 5
6) 4
7) 7
8) 11
9) 12
10) 13

Solution

4^x + 4^(x+1) + 4^(x+2) = 21504
=> 4^x (1+4+4^2) = 21504
=> 4^x = 21504/21
=> 4^x = 1024
=> x = 5
Hence greatest power is 7

Correct Option: 7 Best Solution (5)