<p>A ball of mass m is thrown vertically upward. Another ball of mass 2m&nbsp; is thrown at an angle&nbsp;<span class="equation">\(\theta\)</span>&nbsp;with the vertical. Both the balls stay in air for the same period of time. The ratio of the heights attained by the two balls respectively is&nbsp;<span class="equation">\(\frac{1}{x}\)</span>. The value of x is____​​​​​​​</p>