COMEDK2012MathematicsMathematical Induction
The last digit of 583 !+7²⁹¹ is
Options
- A1
- B2
- C0
- D3
Correct answer
D. 3
Step-by-step solution
We have, 583 ! 0( 10) and 7²=-1( 10) So, (7² )¹⁴⁵ 7¹=(-1)¹⁴⁵ 7¹( 10) 7²⁹¹=-7( 10) 3( 10) So, 583 !+7²⁹¹=3( 10) Hence, last digit is 3 .