Answer:
The number of dimes is 14 and the number of quarters is 7.
Explanation:
Given:
Emily has $3.15 worth of dimes and quarters.
She has twice as many dimes as quarters.
Now, to determine the number of dimes and the number of quarters.
Let the number of quarters be
![x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/mmi228653dkvma4dszwy75q6dvkduzr4zg.png)
And the number of dimes be
![2x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/p20a2g79l7v8fptf663mkk4s0fdb32ioi8.png)
So, the total worth of dimes and quarters = $3.15.
Now, to get the number of dimes and quarters:
According to question:
![0.10(2x)+0.25x=3.15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/sk8aznav81c8z5udsrqvrgm6h11uoh99lp.png)
![0.20x+0.25x=3.15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/76e13ufqc0j1b2weiquvovd2mpy5nse6o9.png)
![0.45x=3.15](https://img.qammunity.org/2021/formulas/mathematics/middle-school/u08gnrkfo79ks5fe8khgimn1tzwjn7gfb2.png)
Dividing both sides by 0.45 we get:
![x=7.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/vh7rrhpqraie3xclv6ofgguik1mxgd7e97.png)
Thus, the number of quarters = 7.
So, the number of dimes =
![2x=2* 7=14.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ppeevybj1i928nnotazth7jqbbtdf5694z.png)
Therefore, the number of dimes is 14 and the number of quarters is 7.