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Let...
x=the number of red bricks
y=the number of blue bricks
Since she bought a total of 100 bricks... x+y=100.
Because the total cost is $560... 5x+7y=560.
Using these two equations, we can use the substitution method to solve for x and y.
x+y=100 ------------------------> x=100-y
subtract y on both sides
Because x=100-y...
this is x
5x+7y=560 (second equation) equals 5( 100 - y )+7y=560
This equation we created has only one variable so we can solve it.
5(100-y)+7y=560
500-5y+7y=560
2y+500=560
2y=60
y=30 blue bricks
Because x=100-y... x=100-30=70 red bricks.
Answer:
320cm³ (option C)
Step-by-step explanation:
The complete image of the question can be found in:
brainly.com/question/16820683
Volume of bird house = volume of a cuboid + volume of a triangular prism
Volume of a cuboid = length × breadth × height
= 8cm × 5cm × 6cm = 240cm³
Volume of triangular prism = ½ base ×height ×length
= ½ × 8×4×5 = 80cm³
Volume of bird house = 240+80
Volume of bird house = 320cm³
Amount of birdseed that will it take to fill the birdhouse = Volume of bird house = 320cm³