The value of each main scale division of a vernier calipers is 1mm and vernier scale divisions are in A.P. 1st division is 0.95mm. 2nd division is 0.9 mm; third division is 0.85 mm and so on. When an object is placed between jaws  of vernier calipers, zero of vernier lies between 3.1 cm and 3.2 cm and 4th division of vernier coincides with main scale division (neglect the zero error ) reading of vernier is