Answer:
The cost of her dinner without tax or tip is $22.
Explanation:
Given:
Anna enjoys having dinner at a restaurant in a town where the sales tax on meals is 10%.
She leaves 15% tip before the sales tax is applied, and the tax is calculated on the pre-tip amount.
She spends a total of $27.50 on her dinner.
Now, to find the cost of her dinner without tax or tip.
Let the cost of dinner without tax or tip be
![x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/mmi228653dkvma4dszwy75q6dvkduzr4zg.png)
So, the tax is:
![10\%\ of\ x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/zwquccrxsoj2go5q8wmzaspeh8kukx2gvo.png)
![=(10)/(100) * x](https://img.qammunity.org/2021/formulas/mathematics/middle-school/y9v7pol3l83mvuqmfb7zzd8xwb6ijnx08p.png)
![=0.10* x](https://img.qammunity.org/2021/formulas/mathematics/middle-school/l4tctbi0t1qf1xkzphwz7hscs1dvsd7xau.png)
![=0.10x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/xaeyl7cl1v0mmr6g13pd1vcjbrpisa8ow8.png)
And, the tip is:
![15\%\ of \ x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/jxn980fhgeb5bqrued3zo9htuz4v7fdeqg.png)
![=(15)/(100) * x](https://img.qammunity.org/2021/formulas/mathematics/middle-school/8w1x1jarj0grlz3o1zobdk2y0gilvhp3hr.png)
![=0.15* x](https://img.qammunity.org/2021/formulas/mathematics/middle-school/fn099103fgoouqkd84ygvfli16vlfn8q3i.png)
![=0.15x.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/zslbn5kf8i5b4u6zius8ma2pqb8fuuloja.png)
As given, she spends a total $27.50 on her dinner.
Now, to get the cost of her dinner without tax or tip:
![x+0.15x+0.10x=27.50](https://img.qammunity.org/2021/formulas/mathematics/middle-school/dnzqqr8jjllbgeq6wywmgfnnjyfdpeiudu.png)
![x+0.25x=27.50](https://img.qammunity.org/2021/formulas/mathematics/middle-school/nv08m02zqw3xom7667m2r604qr31vh4iaa.png)
![1.25x=27.50](https://img.qammunity.org/2021/formulas/mathematics/middle-school/219nsatww6vk93b8fw4pf14odx68w5jcj3.png)
Dividing both sides by 1.25 we get:
![x=22](https://img.qammunity.org/2021/formulas/mathematics/middle-school/qzbn2rp325hop0crv3a5cnvymchyqq20pj.png)
![x=\$22.](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3f3h6munfgkg5kv1nplsupwku8gjl0w7bg.png)
Therefore, the cost of her dinner without tax or tip is $22.