Elitmus
Exam
Numerical Ability
Number System
what is the least value of n for which 99^n begins with 8.
A) 11
b)10
c)9
d) such value not exist for any value for n
Read Solution (Total 9)
-
- 99^1=99
99^2=9801
99^3=970299
99^4=96059601
notice one thing power is 1 number start with 99
power =2 then number start with 98
power =3 then number start with 97
and so on
power =4 then number start with 96
power =5 then number start with 95
power =6 then number start with 94
power =7 then number start with 93
power =8 then number start with 92
power =9 then number start with 91
power =10 then number start with 90
power =11 then number start with 89
so option A is correct
- 9 years agoHelpfull: Yes(57) No(0)
- 99^11 begins with 8. N=8
- 9 years agoHelpfull: Yes(4) No(1)
- value of n would be 11
that start number will start from 8 - 9 years agoHelpfull: Yes(2) No(0)
- In a more traditional way, this problem can be solved like below.
99(100 - 1) = 9900-99= 9801
9801(100 - 1) = 980100-9801= 971299
971299(100 - 1) = 97129900 - 971299 = 96157601
.....
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Just observe the pattern, 98, 97, 96, .... for power of 2, 3, 4, .... So for 90 the power could be 10. So for 11, you get a number starts with 8. ans.(a) - 9 years agoHelpfull: Yes(1) No(0)
- 9
n=11,12,13,14,15,16,17,18,19 (there will also b another values like 20,21... but it ask minimum ) - 9 years agoHelpfull: Yes(0) No(1)
- such value not exit for any value of n
- 9 years agoHelpfull: Yes(0) No(4)
- great answer @abhishek
- 9 years agoHelpfull: Yes(0) No(0)
- good explanation @ abhishek
- 9 years agoHelpfull: Yes(0) No(0)
- (A) 11 is the right answer because the starting digit is 8
- 8 years agoHelpfull: Yes(0) No(0)
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