SOLUTION: Mrs Kumar paid $114 for 4 kg of prawns and 3 kg of crabs. If she had bought 3 kg of prawns and 5 kg of crabs instead, she would have to pay $21 more. What was the cost of 1 kg of c

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Question 989003: Mrs Kumar paid $114 for 4 kg of prawns and 3 kg of crabs. If she had bought 3 kg of prawns and 5 kg of crabs instead, she would have to pay $21 more. What was the cost of 1 kg of crab?
Found 2 solutions by zhagi17, macston:
Answer by zhagi17(16) About Me  (Show Source):
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
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P=price/kg of prawns; C=price/kg of crabs
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4kg(P)+3kg(C)=$114 Multiply this by 3.
12kg(P)+9kg(C)=$342 Call this Equation 1.
3kg(P)+5kg(C)=$135 Multiply this by 4.
12kg(P)+20kg(C)=$540 Call this Equation 2.
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Subtract Equation 1 from Equation 2:
. 12kg(P)+20kg(C)=$540
-(12kg(P)+ 9kg(C)=$342)
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11kg(C)=$198
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C=$18/kg
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ANSWER: One kilogram of crab cost $18.