The number 777…7 is formed by writing the digit 7 forty times. The remainder when this number is divided by 9 is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1
Since \(10 \equiv 1 \pmod{9}\), every power of 10 is also congruent to 1. So a number leaves the same remainder as the sum of its digits on division by 9.
\(\text{Sum of digits} = 40 \times 7 = 280\)
\(280 = 9 \times 31 + 1\)
So the remainder is 1.