TCS
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Numerical Ability
Sequence and Series
how many three digit numbers can be form from digit 1-9 strictly in increasing order and follows an A.P.
A) 9
B)14
C)16
D) 12
Read Solution (Total 7)
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- numbers are 123 135 147 159 234 246 258 345 357 369 456 468 567 579 678 789
hence option c)16 - 8 years agoHelpfull: Yes(10) No(18)
- can anyone explain the ans of this question??
- 7 years agoHelpfull: Yes(2) No(0)
- here we need to take common difference of 1,2,3,4..
e.g in 123
common difference is 2-1=1 and 3-2=1
again with common difference 2
a new number is 135
so there are 4 such numbers with starting digit 1
now with starting digit 2 we can proceed the same way but we need to remember that the number must be in increasing order and Within 1 to 9...
- 8 years agoHelpfull: Yes(1) No(2)
- answer is 16
123
234
345
456
567
678
789
135
357
579
246
468
147
258
369
159 - 7 years agoHelpfull: Yes(1) No(1)
- 111,222,.....,999
- 8 years agoHelpfull: Yes(0) No(3)
- answer is 16
- 5 years agoHelpfull: Yes(0) No(0)
- 7 with common difference 1
123,234,345,456,567,678,789
5 with common difference 2
135,246,357,468,579
3 with common difference 3
147,258,369
1 with common difference 4
159
In total 16 numbers - 2 years agoHelpfull: Yes(0) No(0)
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