(i) The mathematical expression to show Mrs. Chamling's earnings and expenses can be written as:
Weekly earnings = Rs 6,000
Daily food expenses = Rs 250
Daily transportation expenses = Rs 75
Total weekly expenses = (Rs 250 + Rs 75) x 7 = Rs 2,275
Total weekly savings = Weekly earnings - Total weekly expenses
= Rs 6,000 - Rs 2,275
= Rs 3,725
(ii) Mrs. Chamling saves Rs 3,725 in a week.
As for the second part of the question, I am not sure what is being asked. The sentence is incomplete and unclear. Please provide more information or context so I can assist you better.