Dear Student,
In this case 50 tonnes of wheat has been delivered in two instalments, first in the month of December consisting of 40 tonnes of wheat and second consisting of 10 tonnes in the next month i.e. January. However, as per Section 38 of the Sale of Goods Act, 1930, unless otherwise agreed in the contract; the buyer of goods is not bound to accept the delivery of goods in instalments.
Thus, in the above case, the buyer has the right to reject the whole lot of goods as they were delivered in instalments which was not agreed upon.
Hope this answers your query.
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