Samosa stall earning

Samosa stall

If a samosa stall sells 300 samosas daily

and the cost of one samosa is Rs 10.

10 x 300 = 3 thousand rupees per day sales 

- 90 thousand rupees per month

30 thousand rupees per month

60 thousand profit

How much does it cost to make 1 Samosa?

What is the revenue margin of samosa?