SOLUTION: Tyrel and dalia bought some pens and pencils. Tyrel bought 4 pens and 5 pencils which cost her $6.71... Dalia bought 5 pens and 3 pencils which cost her $7.12.... let a equal the c

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Tyrel and dalia bought some pens and pencils. Tyrel bought 4 pens and 5 pencils which cost her $6.71... Dalia bought 5 pens and 3 pencils which cost her $7.12.... let a equal the c      Log On


   

Question 387215: Tyrel and dalia bought some pens and pencils. Tyrel bought 4 pens and 5 pencils which cost her $6.71... Dalia bought 5 pens and 3 pencils which cost her $7.12.... let a equal the cost of one pen and let b eual the cost of one pencil
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Tyrel and dalia bought some pens and pencils.
Tyrel bought 4 pens and 5 pencils which cost her $6.71...
Dalia bought 5 pens and 3 pencils which cost her $7.12....
let a equal the cost of one pen and let b equal the cost of one pencil
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Equations:
4a + 5b = 671 cents
5a + 3b = 712 cents
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Multiply 1st by 5
Multiply 2nd by 4
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20a + 25b = 5*671
20a + 12b = 4*712
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Subtract 2nd from 1st and solve for "b":
13b = 507
b = 39 cents (price of one pencil)
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Substitute into 4a+5b = 671 to solve for "a":
4a + 5*39 = 671
4a = 476
a = 119 cents (price of one pen)
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Cheers,
Stan H.