Re: When the decimal point of positive number N is moved 2 places to the l
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16 Sep 2025, 23:12
Let N be a positive number. When the decimal point of N is moved 2 places to the left, the result is equal to N divided by 100 , or $\(\frac{N}{100}\)$.
According to the problem, this result is equal to $\(\frac{6}{N-1}\)$. We can set up the following equation:
$$
\(\frac{N}{100}=\frac{6}{N-1}\)
$$
To solve for N , we can cross-multiply:
$$
\(\begin{aligned}
& N(N-1)=6 \cdot 100 \\
& N^2-N=600
\end{aligned}\)
$$
Now, we can rearrange the equation into a standard quadratic form:
$$
\(N^2-N-600=0\)
$$
We can solve this quadratic equation by factoring. We are looking for two numbers that multiply to -600 and add up to -1 . The numbers are 24 and -25 .
So, we can factor the equation as:
$$
\((N+24)(N-25)=0\)
$$
This gives us two possible values for N :
$$
\(\begin{aligned}
& N+24=0 \Rightarrow N=-24 \\
& N-25=0 \Rightarrow N=25
\end{aligned}\)
$$
Since the problem states that N is a positive number, the only valid solution is $\(\mathbf{N}=\mathbf{2 5}\)$.
Let's check the answer:
- Moving the decimal point of 25 two places to the left gives 0.25.
- The expression $\(\frac{6}{N-1}\)$ becomes $\(\frac{6}{25-1}=\frac{6}{24}=0.25\)$.
Since both sides are equal, the value of $N$ is \(25 \).