240:(x:15)-18=42

To solve the equation \(240:(x:15)-18=42\), let's rewrite it more clearly. First, let's interpret ':' as division and let's get rid of the double division to simplify the expression. It seems that the expression could mean \( \frac{240}{\frac{x}{15}} - 18 = 42 \).

Here are the steps to solve the equation:

\[ \frac{240}{\frac{x}{15}} - 18 = 42 \]

First, we'll solve the double fraction by multiplying the numerator by the reciprocal of the denominator:

\[ \frac{240}{1} * \frac{15}{x} - 18 = 42 \]

This simplifies to:

\[ \frac{240 * 15}{x} - 18 = 42 \]

Next, calculate \(240 * 15\):

\[ 3600/x - 18 = 42 \]

Now, we will isolate the fraction by adding 18 to both sides of the equation:

\[ 3600/x = 42 + 18 \]

\[ 3600/x = 60 \]

Next, we will solve for x by multiplying both sides of the equation by x and then dividing by 60:

\[ 3600 = 60x \]

\[ x = 3600 / 60 \]

\[ x = 60 \]

Therefore, the value of x that satisfies the original equation is 60.