Latest TCS Aptitude Question SOLUTION: 7,77,777,7777,77777,777777.... Find last 3 digits of sum of first 26 terms.

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(#M40039750) TCS question Keep an EYE

7,77,777,7777,77777,777777....
Find last 3 digits of sum of first 26 terms.

Asked In TCS shivangi agarwal (9 years ago)

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Read Solution (9) :

mohdzuhiab  (9 years ago)

at unit digit 7 would be coming 26 timing
so, 26*7=182., 2 at unit place
then 25*7=175+ (18 carry)=193
then 24*7=187
therefore answer is 732.,

Is this solution Helpfull? Yes (32) | No (2)  

hardik  (9 years ago)

7, 77, 777, 7777 ….to 26 terms.
Sn=7+77+777+7777+……+to 26 terms
=(7)[1+11+111+……+ to 26 terms]


= (7/9) [(10-1) + (100-1) + (1000-1) +……...+ to n term]

= (7/9) [10+100+1000+……... n terms – (1+1+1+1+…… n terms)

= (7/9) [10+100+1000+………n terms –n]

Is this solution Helpfull? Yes (6) | No   

aman sharma  (9 years ago)

7*26=182 so last digit is 2
7*25+18=193 so 2nd digit is 3
7*24+19=187 so 3rd digit is 7


ans 732

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Narasapu Hari prasad  (9 years ago)

Ans is 732
777*24+77+7=18732

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

Neha Seth  (9 years ago)

Ans is 732

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soumya  (9 years ago)

what formula have you used to get ans:732??

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Shachi  (9 years ago)

unit digit : 2
tens digit : 3
hundreds digit:7

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Tamal Chakraborty  (9 years ago)

777
77
7
------
861

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pavan  (8 years ago)

7777
777
77
-------
247

Is this solution Helpfull? Yes | No (1)  

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