To solve this problem, we must set up a system of equations. In this case, let's let Maggie's age be represented by the variable m and her brother's age be represented by the variable b. We are told that the sum of their ages is 24, which gives us our first equation: m + b = 24. We can construct our next equation from the first sentence of given information: b = 2m - 3. This makes our system of equations:
m + b = 24
b = 2m - 3
To solve, we are going to substitute the value for b in terms of m given by the second equation into the first equation for the variable b.
m + b = 24
m + 2m - 3 = 24
To simplify, we must first combine the variable terms on the left side of the equation using addition.
3m - 3 = 24
Next, we should add 3 to both sides of the equation to get the variable term alone on the left side of the equation.
3m = 27
Finally, we should divide both sides by 3 in order to get the variable m alone.
m = 9
Therefore, Maggie is 9 years old (using the first equation and substituting in this value you can find that her brother is 15 years old).
Hope this helps!
Answer:
3 miles/h
Step-by-step explanation:
<u>You can set up a division problem to represent the equation.</u>
12 miles÷4 hours=3 miles/hr
do you have any more information?
9514 1404 393
Answer:
274 mL
Step-by-step explanation:
Often medical solutions expressed as a percentage are not really a percentage as such. A percentage is the ratio of two quantities with the same units.
Here, the context given by the problem suggests the "25%" solution is really (25 g)/(100 mL). That is, the units are grams and milliliters--different units.
With that assumption, we want to find the volume (v) of solution needed to deliver 6 g of medicine. An appropriate proportion* is ...
v/(6 g) = (100 mL)/(25 g)
v = (6 g)(100 mL)/(25 g) = 24 mL
So, the total volume of the infusion is ...
250 mL +24 mL = 274 mL
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* The concentration is given in terms of g/mL, but we have used a proportion that is mL/g. The reason for that is we want the variable to be in the numerator of the ratio. The variable here represents volume, so we have written the proportion with volumes in the numerators.
Having the variable in the numerator means the equation can be solved in one step--by multiplying by its denominator.
