A shopkeeper purchased 1600 mangos at the rate of ₹ 120 per dozen. Out of these, he sold 900 mangoes at ₹15 per mango and the remaining mangoes at ₹14 per mango. His gain percentage is:

​Total number of mangoes purchased = 1600

Cost price per dozen = ₹120

900 mangoes are sold at ₹15 per mango.

Remaining mangoes (1600 - 900 = 700) are sold at ₹14 per mango.

Cost Price (CP) = Number of dozens of mangoes × Price per dozen.

Profit % (Gain %) = $$\frac{\text{SP} - \text{CP}}{\text{CP}} \times 100$$  ​