Question

I am a number between 20 and 30. if you divide 47 and 92 by me, the remainders are 3 and 4, respectively. what number am I ?

Answer 1

When we divide 47  by the required number then the remainder =  3 
∴ 47 - 3 = 44
so the number divides 44 exactly
Between 20 & 30 only 22 divides the number 44 exactly
Similarly,
92 - 4 = 88
Between 20 & 30 only 22 divides the number 88 exactly
so the required number is 22