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?
David's revenue for the 50 kilograms of rice is $1.20 x 50 = $
<gadget id="calculator">1.20*50</gadget>
<output>60</output>
60.
So, his profit is $60 - $50 = $
<gadget id="calculator">60-50</gadget>
<output>10</output>
10.

<result>10</result>