Step-by-step explanation:
first a little help, how they got the equations :
in total they need 15 liters.
so, whatever x and y are, but together they must be 15 L.
x + y = 15
then, we are mixing x liters of 20% alcohol with y liters of 100% alcohol, that have to result in a 40% solution of (x+y) liters :
0.2x + y = 0.4(x+y)
we know from the first equation that x+y = 15, so the second equation is actually
0.2x + y = 0.4 × 15 = 6
so, we have
x + y = 15
0.2x + y = 6
do you notice something ? there is a "+ y" in both equations.
so we can actually subtract the second equation from the first, eliminate y and solve for the remaining x. and then use one of the original equating to get also y :
x + y = 15
- 0.2x + y = 6
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0.8x 0 = 9
0.8x = 9
x = 9/0.8 = 11.25 liters
x + y = 15
11.25 + y = 15
y = 15 - 11.25 = 3.75 liters
100/25= 4
9 out of 25 didnt like it
9 times 4= 36 didnt like it
100-36=64 like the book
When the amount found when Bob measured [5.12] is divided by the actual [6] the result is .853333, which is the percentage that Bob measured as compared to the actual. amount of error is 15% (100%-85%)
Answer:
60%
Step-by-step explanation:
The original was $20 to $12, so if you divide both prices by 2 (to make one side 10 and the other the simplified percentage) you get:
10 to 6.
Percentages are typically x% out of 100, so if you multiply both by 10 you get:
100 to 60. All you have to do now is change the format to percentage instead of a fraction (60/100) and the answer is 60%.
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3m and 4m
Since 3m and 4m are attached to the same variable, they are like terms, since they can appropriately be combined.
