Latest TCS Aptitude Question SOLUTION: X=99^n. i)Find the least value of n for which the 1st digit of X is 8. ii)Find the least value of n for which the 1st digit of X is 7.

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(#M40028922) TCS Logical Reasoning question Keep an EYE

X=99^n.
i)Find the least value of n for which the 1st digit of X is 8.
ii)Find the least value of n for which the 1st digit of X is 7.

Asked In TCS Arindam Dhara (10 years ago)

Unsolved Read Solution (12)

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Read Solution (12) :

MANOJ KUMAR PANDIT  (10 years ago)

1)99^11=8.....
2)99^23=7..
so n=11 and 23.

Is this solution Helpfull? Yes (18) | No (27)  

ashu gupta  (10 years ago)

there are no such values of n because:
99^2=9801
99^3=970299
99^4=96059601
and so on..

Is this solution Helpfull? Yes (15) | No (7)  

RAKESH  (10 years ago)

there is no value of x which will satisfy the eqn
for both cases,
NO SOLN

Is this solution Helpfull? Yes (11) | No (4)  

RAKESH  (10 years ago)

X=99^n
=(3*3*11)^n
=3^2n*11^n
soln 1) 11^n gives 1 as last digit for any value of n
3^2n always gives 3,9,7,1 as last digit for all n
there is no soln for 1st case
2)11^n gives 1 as last digit for any value of n
3^2n will give 7 as last digit for 2n=3(least value)
so n=3/2 is the reqd answer

Is this solution Helpfull? Yes (7) | No (19)  

selva  (10 years ago)

11,23.these two values has 8& 7

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

Suman Saurabh  (10 years ago)

i) least value of n for which the 1st digit of x is 8=2
ii)least value of n for which the 1st digit of x is 7=3

Is this solution Helpfull? Yes (1) | No (18)  

Guru Pranav  (10 years ago)

For the first one the answer is 11

Secnd one answer will be 23.

Is this solution Helpfull? Yes (1) | No (3)  

sathish   (10 years ago)

@ manoj how u put ^11 bcz 99^11 gives a big value...cant get it

Is this solution Helpfull? Yes | No (3)  

Pratyusha Bhadra  (10 years ago)

23 & 11...how r u gtng dis manoj?ne shrt trick?

Is this solution Helpfull? Yes | No (1)  

Sana  (10 years ago)

No Soln For this question

Is this solution Helpfull? Yes | No (3)  

Sri Harsha  (9 years ago)

we get only 9 in the first digit..so none is the answer

Is this solution Helpfull? Yes | No (1)  

  (4 years ago)

i got the answer her we go
first of all "1st digit of X is not unit digit of X"
for example say y=342170 so this number has 1 st digit as 3 and unit digit as 0
i think you got the point
now let's come the point
99^n
n=1 99 i.e 99^1
n=2 9801 i.e 99^2
n=3 970299 .....
n=4 96059601
n=5 9509900499 ..
....
....
......................
n=1 99
n=2 98
n=3 97
n=4 96
and so on

..........
n=11 89
at 99^11 the answer of 99^11 is starting with 8
so answer is 11
as well as for 1st digit to be 7 is at 23
from above explaination reader may think that 7 come at 99^21 only. but it wont come
thank you

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