COMEDK20269 May 2026Morning ShiftMathematicsBinomial TheoremActual
The remainder when 7¹⁰³ is divided by 25 is
Options
- A7
- B18
- C1
- D-1
Correct answer
B. 18
Step-by-step solution
We need to find the remainder when 7¹⁰³ is divided by 25 . We can write 7¹⁰³ as 7 7¹⁰² = 7 (7^2)⁵¹ . We know that 7^2 = 49 -1 25 . Raising both sides to the power of 51 , we get: (7^2)⁵¹ (-1)⁵¹ 25 7¹⁰² -1 25 Multiplying both sides by 7 , we get: 7¹⁰³ -7 25 To find the positive remainder, we add 25 to -7 : -7 + 25 = 18 Thus, the remainder when 7¹⁰³ is divided by 25 is 18 . Answer: 18