Answer is (molecular weight)/6
Potassium Dichromate is used to standardize Sodium Thiosulfate solutions. In acidic solution, Potassium Dichromate oxidizes Potassium Iodide to Iodine; the Iodine thus generated can then be titrated with the Thiosulfate solution using Starch Indicator:
Cr2O72- + 6 I- + 14 H+ → 2 Cr3+ + 3 I2 + 7 H2O
Since each molecule of it is releasing 6 electrons its equivalent wt is m.wt/6
K2Cr2O7 Cr is in 6+ it is converted in to Cr3+ that is accepting 3 e- for two Cr3+ 6 e-s.