Medium
On dividing each of 12 and 23 by a number greater than 1, we get the same remainder. What is the remainder?
Explanation
Explanation
If dividing both 12 and 23 by the same number gives equal remainders, the divisor must exactly divide their difference (23-12=11). Since 11 is prime, the divisor is 11, and dividing 12 by 11 gives a remainder of 1.
PRO TIP
Re-check your working by substituting the answer back into the original question.