KCET2010MathematicsMathematical Reasoning
The least positive integer x satisfying 2²⁰¹⁰ 3 x( 5) is
Options
- A3
- B4
- C1
- D2
Correct answer
A. 3
Step-by-step solution
Since, we know that 2² -1( 5) ( 2²+1 . divisible by 5 ) Now, 2²⁰¹⁰= (2² )¹⁰⁰⁵ (-1)¹⁰⁰⁵( 5) 2²⁰¹⁰ -1( 5) -1 2²⁰¹⁰( 5) But 2²⁰¹⁰ 3 x( 5) -1 3 x( 5) (by transitive relation) x=3