Answer: 12 blue marbles
Step-by-step explanation: Set up a proportion.
4/5 = x/15
Solve for x, the number of blue marbles. Cross multiply. You will get 60 = 5x
Divide by 5 on each side.
x = 12
There are 12 blue marbles.
Answer:
x < -4 or x > 8
On a number line, make two arrows:
1) going towards left from -4 with an open circle at -4
2) going towards right from 8 with an open circle at 8
Step-by-step explanation:
l -4 +2x l -3 > 9
l -4 +2x l > 12
l 2x - 4 l > 12
2x - 4 > 12
2x > 16
x > 8
-2x + 4 > 12
-2x > 8
x < -4
On a number line, make two arrows:
1) going towards left from -4 with an open circle at -4
2) going towards right from 8 with an open circle at 8
Answer:
6(2x - 5)
Step-by-step explanation:
The greatest common factor of 12x and 30 is 6.
12x - 30 = 6(2x - 5)
Answer:
472 3/4
Step-by-step explanation:
Consider the meaning of "one, and one more". That does not mean zero (1-1). Rather, it means two (1+1).
__
Then 3/4 and 472 more is ...

Eric has 472 3/4 buckets filled with sand.
_____
The problem statement here seems to be focused on the filled buckets, rather than the sand stockpile that Eric is working from. The amount in that stockpile is being reduced by the amount that is being used to fill buckets. In short, whether you add or subtract depends on what you're trying to figure.