question_answer

If the division \[N\div 5\] leaves a remainder of 4, what might be the one's digit of N? Suppose that the division \[N\div 5\] leaves a remainder of 4 and the division \[N\div 2\] leaves a remainder of 1. What must be the one's digit of N

Answer:

     

If remainder = 4, then the one?s digit of ?N? must be either 4 or 9.

For

\[N\div 5,\]

remainder = 4

One?s digit can be 4 or 9.                   ...(i)

Again, for N ÷ 2, remainder = 1

N must be an odd number.

So, one?s digit of N must be 1, 3, 5, 7 or 9. ...(ii)

From (i) and (ii), the one?s digit of N must be 9.