What is x when 42 divided by x equals 78?

To find the answer, just divide the dividend by the quotient: 42 ÷ 78 = 0.53846153846154

To prove this, let's compute 42 divided by 0.53846153846154: $\frac{42}{0.53846153846154} = 78$

How does it work?

Asking what the value of x could be when 42 divided by x gives a result of 78, is equivalent to solving the following equation:

$\frac{42}{x} = 78$

Multiply both sides by x: $\frac{42 x}{x} = 78 x$
$\frac{42 x}{x}$ is equivalent to $\frac{x}{x} \times 42$ , which simplifies to $1 \times 42$ (or just $42$ ).
Thus, the equation becomes: $42 = 78 x$
To find x, divide both sides by 78: $\frac{42}{78} = \frac{78 x}{78}$
Which gives, after simplification: $0.53846153846154 = x$ (or $x = 0.53846153846154$ )

So, if the dividend is 42 and the quotient is 78, the divisor is 0.53846153846154.