What is the ratio for crayons to erasers?
1 answer:
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First, translate the words you're given into math: 2x-y = 60% of 5y.
60% = 60/100 = 0.60.
0.60(5y) = 3y
2x-y = 3y
>> If this is the SAT and you have to do percentage by hand, you can always use fractions. So, 60% = 60/100 = 6/10 = 3/5.
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Another quick percentage trick is that 10% of anything is just that number with the decimal point moved to the left one space. For ex: 10% of 5 = 0.5. And then you can multiply 0.5 by 6 (because 10%*6 = 60%) to get 3.
Back to the problem:
Now you have 2x-y = 3y. You are looking for what
equals to. Start by separating the x and y variables by putting them on opposite sides of the equal sign:
2x-y = 3y
2x = 4y
You want x and y on one side and numbers on the other side. You also want y to be on the top of the fraction. What you want to do is divide both sides by x first:
Finally, isolate the variables by dividing by 4 on both sides:
The answer is C) 1/2
60% = 60/100 = 0.60.
0.60(5y) = 3y
2x-y = 3y
>> If this is the SAT and you have to do percentage by hand, you can always use fractions. So, 60% = 60/100 = 6/10 = 3/5.
Another quick percentage trick is that 10% of anything is just that number with the decimal point moved to the left one space. For ex: 10% of 5 = 0.5. And then you can multiply 0.5 by 6 (because 10%*6 = 60%) to get 3.
Back to the problem:
Now you have 2x-y = 3y. You are looking for what
2x-y = 3y
2x = 4y
You want x and y on one side and numbers on the other side. You also want y to be on the top of the fraction. What you want to do is divide both sides by x first:
Finally, isolate the variables by dividing by 4 on both sides:
The answer is C) 1/2