Answer:
x = 25
Step-by-step explanation:
Since CQ is parallel to BR and intersects the other 2 sides then it divides those 2 sides proportionally, that is
[tex]\frac{BQ}{QD}[/tex] = [tex]\frac{RC}{CD}[/tex] , substitute values
[tex]\frac{24}{40}[/tex] = [tex]\frac{15}{x}[/tex] ( cross- multiply )
24x = 600 ( divide both sides by 24 )
x = 25