It is 9:4.
Reason: divide both numbers by a common multiple, which is 7.
They are simple linear equations with one unknown, lets tackle them, one step at the time solving for the unknown:
4x - 2(x - 5) = x + 13
4x - 2x + 10 = x + 13
2x + 10 = x + 13
2x - x = 13 - 10
x = 3
that is the solution.
3(6 - x) - 4 = 5x + 2(7x + 3)
18 - 3x - 4 = 5x + 14x + 6
14 - 3x = 19x + 6
14 - 6 = 19x + 3x
8 = 22x
x = 8/22 = 4/11
Answer:
They are both correct
Step-by-step explanation:
It's interpretation of the concept. In common practice multiplying by 10 means you add a zero and that's what we teach 10 year olds. But what does adding a zero mean? It means adding a place value and that's what you learn when you are
So in both examples just add a decimal:
2.0 x 10 = 20.
0.2 x 10 = 2.0
In conclusion, it depends on the level of precision required in the discussion and the level of maturity as to who is correct in their examples. If you are teaching 3rd graders math, by all means you add a zero. If you are discussing physics you are shifting over a place value.
To solve, set up a proportion
3.25 cups x cups
---------------- = ---------------
13 servings 28 servings
Now cross multiply
13x = 28 * 3.25
Simplify.
13x = 91
Divide both sides by 13
x = 7 cups
To check your answer, use proportions again, but change the left side to 4.5 cups over 18 servings, use the same steps, if the answer is the same as above, then the answer is correct
