A team of workers was employed by a contractor who undertook to finish 360 pieces of an article in a certain number of days. Making four more pieces per day that was planned, they could complete the job a day ahead of schedule. How many days did they take to complete the job when they are making 36 more pieces per day?
1). 10 days
2). 8 days
3). 9 days
4). 6 days
Let’s assume they make x pieces per day
So, number of days to finish the article = 360/x
Now, pieces = x + 4
So number of days to finish the article = 360/(x + 4)
Given:
$(\begin{array}{l} \frac{{360}}{x} - \frac{{360}}{{\left( {x + 4} \right)}}\ = 1\\ \Rightarrow {x^2} + 4x - 1440\; = 0 \end{array})$
⇒ x = 36
Now, pieces = x + 36 = 36 + 36 = 72
So number of days to finish the article = 360/72 = 5 days.