SOLUTION: tyrels and dalia bought some pens and pencils. tyrel bought 4 pensand 5 pencils, which cost him $6.71. dalia bought 5 pens and 3 pencils, which cost her $7.12. Let A equal the pric

Question 128099: tyrels and dalia bought some pens and pencils. tyrel bought 4 pensand 5 pencils, which cost him $6.71. dalia bought 5 pens and 3 pencils, which cost her $7.12. Let A equal the price of a pen. let B equal the price of a pencil.
a. write an equation that relates the number of pens and pencils tyrel bought to the amount he paid for them.
b. write an equation that relates the number of pens and pencils dalia bought to the amount she paid for them.
c. solve the system you wrote for parts (a) and (b) to find the price of a pen and the price of a pencil.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
tyrel bought 4 pensand 5 pencils, which cost him $6.71. dalia bought 5 pens and 3 pencils, which cost her $7.12. Let A equal the price of a pen. let B equal the price of a pencil.
a. write an equation that relates the number of pens and pencils tyrel bought to the amount he paid for them.
EQUATION:
4A + 5B = 6.71
5A + 3B = 7.12
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Multiply the 1st equation by 5 and the 2nd equation by 4 to get:
20A + 25B = 5*6.71
20A + 12B = 4*7.12
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Subtract the 2nd equation from the 1st to get:
13B = 5.07
B = 39 cents (price of a pencil)
-------------------
Substitute to solve for A:
4A + 5(0.39) = 6.71
4A = 4.76
A = $1.19 (price of a pen)
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Cheers,
Stan H.

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