Okay. You can decompose 749 with these ways:
700 + 40 + 9
or
500 + 200 + 40 + 9
At the end of the year, you pay 320 dollars.Just multiply 15 by 12, and add the sum to 140. Hope this helps!
Answer: Amber use 30 feet of basic tiles and 6 feet of decorative tiles.
Step-by-step explanation:
Let x be the foot of basic tiles and y be the foot of decorative tiles.
Now, according to the question, we have the following equations
![x+y=36\\y=36-x\ .......(1)\\\\8x+20y=36\times10\\2x+5y=90.......(2)\ \ \ [\text{divide equation by 4}]](https://tex.z-dn.net/?f=x%2By%3D36%5C%5Cy%3D36-x%5C%20.......%281%29%5C%5C%5C%5C8x%2B20y%3D36%5Ctimes10%5C%5C2x%2B5y%3D90.......%282%29%5C%20%5C%20%5C%20%5B%5Ctext%7Bdivide%20equation%20by%204%7D%5D)
Put y=36-x in (2), we get

Hence, Amber use 30 feet of basic tiles and 6 feet of decorative tiles.