• Placement Papers
• /
• TCS

TCS Question Papers: TCS Interview Experience(90) TCS Company Profile

(#M40024658) TCS question Keep an EYE

Find last three digits of 2988^687

Asked In TCS Amrutha Duggirala (10 years ago)

Unsolved Read Solution (9)

Is this Puzzle helpful?   (11)   (5) Submit Your Solution

Read Solution (9) :

Y.Prasanna Chandra Lekha  (10 years ago)

(2988^687)/1000 leaves remainder as the last 3 digits of result
this can be = 988^(4*171+3)=988^3 by cyclicity
this leaves 272 as last 3 digits

Is this solution Helpfull? Yes (5) | No (14)  

tejomay saha  (10 years ago)

please give a proper solution

Is this solution Helpfull? Yes (2) | No (1)  

Durga  (10 years ago)

unit digit of 2988 is 8
The cyclicity of 2,3,7,8 is 4
The cyclicity of 0,1,5,6 is the no. itself
The cyclicity of 4,9 is 2
To check whether the number is divisible by 4 we have to divide the last two digit by 4. Likewise in 687 we have to divide 87 by 4 we get the remainder 3.So we have to put 3 as a power of unit digit i.e. 8(in base number)
8^3=432 therefore the ans is 432

Is this solution Helpfull? Yes | No (8)  

Lakshmi  (10 years ago)

@chandra lekha
Cycle is not repeating at power of 4 right?
then how u taken as multiple of 4 and all...
pls explain...

Is this solution Helpfull? Yes | No   

ipsita saha  (10 years ago)

pls explain properly

Is this solution Helpfull? Yes | No   

sahithi  (10 years ago)

@durga 8^3=512 not 432
so,ans:512

Is this solution Helpfull? Yes | No   

Guru Pranav  (10 years ago)

mine came 592 :p

Is this solution Helpfull? Yes | No   

Surojit Chinya  (10 years ago)

(2988^687)/1000 leaves remainder as the last 3 digits of result
this can be = 988^(4*171+3)=988^3 by cyclicity
this leaves 272 as last 3 digits

Is this solution Helpfull? Yes | No   

Saumashankar Bala  (7 years ago)

ans is 504

Is this solution Helpfull? Yes | No   

Please Login to Read Solution.