Answer :
The system of equation to represent the situation is
x + y = 179
2/3x + 3/4y = 128
How to solve simultaneous equation
- Total copies = 179
- Total weight = 128 pounds
let,
weight of first paperbacks, x = 2/3 pounds
weight of second paperbacks, y = 3/4 pounds
x + y = 179 (1)
2/3x + 3/4y = 128 (2)
- multiply (1) by 3 and (2) by -4
3x + 3y = 537
-4(2/3x) + -4(3/4y) = -512
3x + 3y = 537
-8/3x - 3y = -512
- Add both equations to eliminate y
3x + (-8/3x) = 537 + (-512)
3x - 8/3x = 537 - 512
(9-8)/3x = 25
1/3x = 25
x = 25 ÷ 1/3
x = 25 × 3
x = 75
- Substitute x = 25 into (1)
x + y = 179
75 + y = 179
y = 179 - 75
y = 104
- The system of equations is x + y = 179 and two-thirds x + three-fourths y = 128.
- To eliminate the y-variable from the equations, you can multiply the equation with the fractions by –4 and multiply the other equation by 3.
- There are 104 copies of one book and 75 copies of the other.
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