She knits 18 squares on Monday.
Then she knits 7 more squares each day:
Tuesday: +7, Wednesday: +7, Thursday: +7 and Friday: +7
18 + 7 * 4 = 18 + 28 = 46
Answer: She has 46 squares on Friday.
Yes it is. Ax+By=C is standard form. :)
total=147
a:m
1:6 =7
147÷7=21
21×1=21
alice recycled 21 bottles