Use reasoning to answer the following question.
A sack of rice, which is 50 kilograms, costs $50. If David sells it for $1.20 per kilogram, how much will be his profit?

10
David's revenue for the 50 kilograms of rice is $1.

20 x 50 = $60.

So, his profit is $60 - $50 = $10.

.

The answer is 10