Answer:
250 days.
Explanation:
Let x represent number of days.
We have been given that of the 2,500 tons of ore mined daily at a quarry, 0.4 percent results in a certain pure metal.
Let us find the amount of pure metal by calculating 0.4% of 2500.
![\text{Amount of pure metal}=2500* (0.4)/(100)](https://img.qammunity.org/2021/formulas/mathematics/high-school/antacxbda0rnz8ndi3pz54tbj4iy34mxd7.png)
![\text{Amount of pure metal}=2500* 0.004](https://img.qammunity.org/2021/formulas/mathematics/high-school/8jecksx86lyq702caeahuh3rsrtsbx1c0b.png)
![\text{Amount of pure metal}=10](https://img.qammunity.org/2021/formulas/mathematics/high-school/j4k16ah990k9fcw47m4i8y90nnvwm8bbqn.png)
Amount of pure metal mined in x days will be
.
Since we need total pure metal production equal to 2500 ton, so we can set an equation as:
![10x=2500](https://img.qammunity.org/2021/formulas/mathematics/middle-school/cb74pcmd08lbicb41px3xn0lw04j7pzkil.png)
![(10x)/(10)=(2500)/(10)](https://img.qammunity.org/2021/formulas/mathematics/high-school/t1ltqj444cord4mcrkjes6tcwb17pvr6lj.png)
![x=250](https://img.qammunity.org/2021/formulas/mathematics/high-school/r1avvzmhgc3jrb3xquungxxuc8ngkl60mb.png)
Therefore, it will take 250 days of mining for the total amount of pure metal produced at the quarry to be equal to the daily amount of ore mined.