KCET2009MathematicsBinomial Theorem
The digit in the unit place of the number 2009 !+3⁷⁸⁸⁶ is
Options
- A7
- B3
- C1
- D9
Correct answer
D. 9
Step-by-step solution
The digit in the unit place of (2009)! is 0 . Now, 3¹=3, 3²=9, 3³=27, 3⁴=81 , 3⁵=243 3⁷⁸⁸⁶= (3⁴ )¹⁹⁷¹ 3² The digit in the unit place of 3⁷⁸⁸⁶ is 9 . The digit in the unit place of (2009)! +3⁷⁸⁸⁶ is 9 .