direct and inverse variation
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Answer:
4 workers can do the job in 18 days.
Step-by-step explanation:
The number of days d varies inversely as the number of workers.
We can write it as: [tex]d\: \alpha\: \frac{1}{w} \\d=\frac{k}{w}[/tex]
where k is constant of proportionality
We are given: If it takes 9 days for 8 workers to complete the job, then how many workers would it take to do the job in 18 days.
d = 9, w = 8
d = 18, w =?
First we will find value of k when d = 9, w =8
[tex]d=\frac{k}{w}\\9=\frac{k}{8}\\k=9*8\\k=72[/tex]
The value of k, will remain same as it is constant.
We get k = 72.
So, Now we have d = 18, k = 72 and we need to find w
[tex]d=\frac{k}{w}\\18=\frac{72}{w}\\18w=72\\w=\frac{72}{18}\\w=4[/tex]
So, 4 workers can do the job in 18 days.