First, convert 62.5% to a fraction or decimal. I personally like fractions, so that is what I'll use:
\(62.5\%\) | Convert into fraction by putting whatever is to the left of percent over 100 |
\(\frac{62.5}{100}\) | Multiply each side by 10 on both sides to get rid of the decimal in the numerator |
\(\frac{625}{1000}\div\frac{125}{125}\) | Divide the numerator and denominator by their GCF, 125, to simplify the fraction fully |
\(\frac{5}{8}\) | |
Isn't that nice? \(62.5\%\) simplifies to, in a fraction, \(\frac{5}{8}\). By doing this, we have simplified the problem from \(62.5\%*50\) to \(\frac{5}{8}*\frac{50}{1}\). Now, let's simplify further to get our final answer:
\(\frac{5}{8}*\frac{50}{1}\) | Multiply these fractions by multiplying the numerators and denominators. |
\(\frac{250}{8}\div\frac{2}{2}\) | Put improper in simplest terms by dividing by 2 on both the numerator and denominator |
\(\frac{125}{4}=31\frac{1}{4}=31.25\) | I've placed the final answer in different forms. |
Okay, the answer is clearly \(31.25\). However, there is a trick any percentage of 50. Do this:
This is probably best demonstrated by example. I'll use the problem above, which is \(62.5\%*50\).
Step 1 says to remove the percent sign, so \(62.5\%\) becomes \(62.5\).
Step 2 says divide the result by 2. \(62.5/2= 31.25\). Does this answer seem familiar? It should. It is the same answer as we got above but using different steps.
First, let me show you a wrong approach. I almost fell for it myself:
\(\frac{1}{\frac{6}{2}}=\frac{1}{6}*\frac{1}{2}=\frac{1}{12}\)
This math above is simple, but this would imply that the probability of rolling a 6 is 1/12. Well, you'll see...
If you combine the probabilities of all events occurring, then the probability should be 1. Let's try that with our current answer. Let's test it:
\(\frac{1}{12}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}=1\) | Create a common denominator, first |
\(\frac{1}{12}+\frac{2}{12}+\frac{2}{12}+\frac{2}{12}+\frac{2}{12}+\frac{2}{12}=1\) | Add the numerators |
\(\frac{11}{12}=1\) | This is a false statement |
11/12 is not equal to one 1. Therefore, the probability cannot of rolling a 6 cannot be 1/12. However, there's a trick that we can use. How can we make 11/12=1? That's right, multiply by its reciprocal, 12/11. Therefore, multiply all of your fractions by it:
\(\frac{12}{11}(\frac{1}{12}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6})\)
But wait! WE only need the probability of rolling a 6, so we only need to multiply 12/11 by 1/12!
\(\frac{12}{11}*\frac{1}{12}=\frac{12}{132}=\frac{1}{11}\)
As you'll see below, there are other methods to do this problem. Of course, the method above is what I chose. Isn't it beautiful how multiple approaches still leads to the same final answer?
.\(x=6\hspace{1cm}x=26\)
Here is the original equation:
\(x\pm10=16\)
What is this telling us? This equation is really 2 separate equations. I've laid them out for you:
Now do you understand what \(\pm\) means? It means that you both add and subtract. Solve each equation separately, and you get both values for x. I'll start with the first:
\(x+10=16\) | Subtract 10 on both sides to isolate x |
\(x=6\) | |
Of course, you aren't done yet! You must solve the other equation, too:
\(x-10=16\) | Add 10 on both sides to isolate x |
\(x=26\) | |
Therefore, you have 2 solutions:
\(x=6\) and \(x=26\)
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