In total 180 chairs are ordered for the cost $6000.
The total cost of chairs=$6,000.
In mathematics, a set of simultaneous equations, also known as a system of equations or an equation system, is a finite set of equations for which common solutions are sought.
Let x be the chairs ordered each at $20 and y be the chairs ordered each at $40.
Then equation will be 20x+40y=6000-------(1)
Given that, twice as many $20 chairs as $40 chairs were ordered.
That is 2x=y⇒2x-y=0--------(2)
Multiply equation (2) by 40.
That is 80x-40y=0--------(3)
By adding equation (2) and (3) we get
20x+40y+80x-40y=6000
⇒100x=6000
⇒x=60
Substitute x=60 in equation (2)
That is, 2x=y
⇒y=120
Total number of chairs=x+y=60+120=180 chairs.
Hence, in total 180 chairs are ordered for the cost $6000.
To learn more about simultaneous equations visit:
https://brainly.com/question/16763389.
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