The unit digit in $${\left( {122} \right)^{173}}$$ is ?
A. 2
B. 4
C. 6
D. 8
Answer: Option A
Solution(By Examveda Team)
In this case:122 (powers of the last digit 2 )
21 = 2
22 = 4
23 = 8
24 = 16
25 = 32
26 = 64
27 = 128
28 = 256
29 = 512
……
As you can see, the pattern repeats every 4th power (2, 4, 8, 6).
We have to find 122173
Hence, remainder when 173 is divided by 4 = 1
(which corresponds to the 1st number of the pattern)
Thus, unit digit of 122173 = 2
Related Questions on Number System
Three numbers are in ratio 1 : 2 : 3 and HCF is 12. The numbers are:
A. 12, 24, 36
B. 11, 22, 33
C. 12, 24, 32
D. 5, 10, 15
Join The Discussion