AP EAMCET · Maths · Basic of Mathematics
A three digit number \(n\) is such that the last two digits of it are equal and differ from the first. The number of such \(n\) 's is
- A 64
- B 72
- C 81
- D 900
Answer & Solution
Correct Answer
(C) 81
Step-by-step Solution
Detailed explanation
If the last two digits is 0,0 , then in Ist digit any of the numbers except 0 i.e., 9 numbers If the last two digits is 1,1 , then in Ist digit any of the numbers except 0 and 1 , i.e. 8 numbers \(\therefore\) The total number of numbers \(=9+8 \times 9=81\)
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