3. Rectify the following errors:

1. Credit sales to Mohan ₹7,000 were recorded as ₹7,200.
2. Credit purchases from Rohan ₹9,000 were recorded as ₹9,900.
3. Goods returned to Rakesh ₹4,000 were recorded as ₹4,040.
4. Goods returned from Mahesh ₹1,000 were recorded as ₹1,600.