Number 10.
>
Number 12.
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Number 14.
First, simplify out the brackets:
-20 - 4n = -12
Then, combine like terms by moving the -20 to the other side
-4n = -12 + 20
-4n = 8
Divide by -4 on both sides to isolate the n
n = 8/-4
n = -2
After Sally had given 1/9 of her stamps to Andy, she had 280 stamps (since they now have equal shares). So 280 was 8/9 of what she started with, making the 1/9 she handed over equal to 280/8, that’s 35. And Andy was “under” by the same amount she was “over” an equal share, that’s 35 under matching her 35 over, which is 70 altogether.
By all means use algebra but you may find you can reason a word problem through in words.
divide total cost by length:
0.76 / 3ft = 0.2533 cents per foot
rounded to nearest cent = 0.25 cents per foot