What is x when 42 divided by x equals 10?

To find the answer, just divide the dividend by the quotient: 42 ÷ 10 = 4.2

To prove this, let's compute 42 divided by 4.2: $\frac{42}{4.2} = 10$

How does it work?

Asking what the value of x could be when 42 divided by x gives a result of 10, is equivalent to solving the following equation:

$\frac{42}{x} = 10$

Multiply both sides by x: $\frac{42 x}{x} = 10 x$
$\frac{42 x}{x}$ is equivalent to $\frac{x}{x} \times 42$ , which simplifies to $1 \times 42$ (or just $42$ ).
Thus, the equation becomes: $42 = 10 x$
To find x, divide both sides by 10: $\frac{42}{10} = \frac{10 x}{10}$
Which gives, after simplification: $4.2 = x$ (or $x = 4.2$ )

So, if the dividend is 42 and the quotient is 10, the divisor is 4.2.