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 = $<<1.20*50=60>>60.
So, his profit is $60 - $50 = $<<60-50=10>>10.
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Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
You are solving math problems. Here are some examples of how to solve the task:

Brenda is a vet who needs to spay some cats and twice as many dogs. If she needs to spay 21 animals total today, how many cats does she need to spay?Let c be the number of cats Brenda needs to spay and d be the number of dogs. We know that c + d = 21 and d = 2c.
Substituting the second equation into the first, we get c + 2c = 21
Combining like terms, we get 3c = 21
Dividing both sides by 3, we get c = 7
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Jose threatened to withhold 20% of Amanda's pay if she does not finish her sales report by midnight. If Amanda makes $50.00 an hour and works for 10 hours a day, how much money will she receive if she does not finish the sales report by midnight?If she works for 10 hours a day at an hourly pay of $50, then her total income in a day is $<<10*50=500>>500.
If she doesn't meet the deadline Jose gave her, she'll lose 20/100*$500 = $<<20/100*500=100>>100
She'll receive $500-$100= $<<500-100=400>>400 if Jose cuts out 20% of her pay.
#### 400[END]

Now, solve this next question in the style of the above examples:

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?

### Response:
David's revenue for the 50 kilograms of rice is $1.20 x 50 = $<<1.20*50=60>>60.
So, his profit is $60 - $50 = $<<60-50=10>>10.
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