Answer
x=0.467
Work Step by Step
Set the product of the means equal to the product of the extremes and solve for the variable.
$10\times7=3x \times50$
$70=150x$
$70\div150=150x\div150$
$0.46\underset\uparrow666667=x$
Since the digit to the right of the 3rd significant digit is greater than 5, round up.