Question

Ernie earned $121.50 more than Kaylin. Tria earned $35 less than 3 times the amount Kaylin earned. Ernie, Tria, and Kaylin earned $579 in all. How much did Tria earn?
$98.50
$220.00
$260.50
$330.50

Answer 1

x - Ernie, y - Kaylin, z - Tria

x = y + 121.50

z = 3y - 35

x + y + z = 579

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z = 3 y - 35      =>   - 3 y + z = -35

y + 121.50 + y + z = 579

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- 3 y + z = - 35        / · ( -1 )

 2 y + z = 457.50     (we will use the elimination method) 

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3 y - z = 35

2 y + z = 457.50

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5 y = 492.5,            y = 492.5 : 5 = 98.5

z = 3 · 98.5 - 35

z = 260.5

Tria earned $260.5 

Answer 2

C)260.50
Step by step explanation
Let "x" be the amount earned by Ernie
Let "y" be the amount earned by Kaylin
Let "z” be the amount earned by Tria

Now let’s form the equations

x=y + 121.50 (1)

z=3y- 35 (2)

x + y + 2= 579 (3)

Now plug in x = y + 121.50, in the third equation.

y + 121.50 + y + z =579

2y + z = 457.50

From the second equation 3y - z = 35

2y + z =457.50

3y - z = 35

5y = 492.5

Dividing both sides by 5 we get

y = 98.50

Now let’s find how much Tria earned.

z = 3*98.5 - 35

z = $260.50