Answer:
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![\boxed{Rs \: 800}](https://tex.z-dn.net/?f=%20%5Cboxed%7B%3C%2Fstrong%3E%3Cstrong%3ER%3C%2Fstrong%3E%3Cstrong%3Es%20%5C%3A%20800%7D)
</h3>
Step-by-step explanation:
Cost price of three machines with repairment charge ( CP ) = 5400 × 3 + 4000
= Rs 20200
Selling price of 1 machine = Rs 7000
Selling price of 3 machines ( S.P )= Rs 7000 × 3
= Rs 21000
Since , SP > CP , he made a profit
Profit = SP - CP
= Rs 21000 - Rs 20200
= Rs 800
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Further more explanation
<u>Profit </u><u>and </u><u>loss</u>
In any business , owners have intension to have profit by selling articles. The price at which an article is purchased is called it's Cost price ( C.P ) and the price at which it is sold is called Selling price ( S.P ).
If the selling price is less than cost price of an article then there is a loss.
![\mathrm{Loss \: = \: Cost \: Price \: (C.P) - Selling \: Price \: (S.P)}](https://tex.z-dn.net/?f=%20%20%5Cmathrm%7B%3C%2Fstrong%3E%3Cstrong%3EL%3C%2Fstrong%3E%3Cstrong%3Eoss%20%5C%3A%20%20%3D%20%20%5C%3A%20%3C%2Fstrong%3E%3Cstrong%3EC%3C%2Fstrong%3E%3Cstrong%3Eost%20%5C%3A%20%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3Erice%20%5C%3A%20%28%3C%2Fstrong%3E%3Cstrong%3EC.%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3E%29%20-%20%3C%2Fstrong%3E%3Cstrong%3ES%3C%2Fstrong%3E%3Cstrong%3Eelling%20%5C%3A%20%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3Erice%20%5C%3A%20%28%3C%2Fstrong%3E%3Cstrong%3ES.%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3E%29%7D)
If the selling price is more than cost price of an article then there is a profit ( gain )
![\mathrm{Profit = Selling \: Price \: (S.P) - Cost \: Price \: (C.P)}](https://tex.z-dn.net/?f=%20%5Cmathrm%7B%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3Erofit%20%3D%20%3C%2Fstrong%3E%3Cstrong%3ES%3C%2Fstrong%3E%3Cstrong%3Eelling%20%5C%3A%20%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3Erice%20%5C%3A%20%28%3C%2Fstrong%3E%3Cstrong%3ES.%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3E%29%20-%20%3C%2Fstrong%3E%3Cstrong%3EC%3C%2Fstrong%3E%3Cstrong%3Eost%20%5C%3A%20%3C%2Fstrong%3E%3Cstrong%3EP%3C%2Fstrong%3E%3Cstrong%3Erice%20%5C%3A%20%28%3C%2Fstrong%3E%3Cstrong%3EC.P%3C%2Fstrong%3E%3Cstrong%3E%29%7D)
So, If S.P > C.P, there is profit in dealing.
If C.P > SP , there is loss in dealing.
Hope I helped!
Best regards!!