Question #13213

0.04x + 0.02y = 78
x + y = 2800
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solve the system and you get your answers
sum at 4% = x
sum at 2% = y

Expert's answer

0.04x + 0.02y = 78 (1)

x + y = 2800& (2)

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(2) ==>

x = 2800 - y

(1):

0.04(2800 - y) + 0.02y = 78 ==>

112 - 0.04y + 0.02y = 78 ==>

-0.02y = -34 ==>

y = 1700.

So,

x = 2800 - 1700 = 1100.

x + y = 2800& (2)

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(2) ==>

x = 2800 - y

(1):

0.04(2800 - y) + 0.02y = 78 ==>

112 - 0.04y + 0.02y = 78 ==>

-0.02y = -34 ==>

y = 1700.

So,

x = 2800 - 1700 = 1100.

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