Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case. 

4

The greatest number which leaves same remainders on dividing a, b, c & d is HCF [(b-a), (c-b), (d-c)]

Now, a, b , C and D,   HCF [(b-a), (c-b) , (d-c)]

Required number = H.C.F. of (91 - 43), (183 - 91) and (183 - 43)

                         = H.C.F. of 48, 92 and 140 = 4.