At a cricket test match $\frac{2}{7}$th of the spectators were in a covered place while 15000 were in open. The total number of spectators is [[1]].

Given at a cricket test match $\frac{2}{7}$th of the spectators were in a covered place while 15000 were in open.
Number spectators covered $=\frac{2}{7}$th of the total. 
Thus, the number of spectator uncovered in fraction is,
$=1-\frac{2}{7}$ 

 $=\frac{7-2}{7}$ 

 $=\frac{5}{7}$  

Number of spectators in open = 15000
Number of spectators in open = total number of spectators $\times$ Fraction of spectators in open
Let the total number of spectator = x

Thus,
$15000=x\times \frac{5}{7}$ 

$\Rightarrow x=15000÷\frac{5}{7}$

⇒$x=\frac{15000}{1}\times \frac{7}{5}$ 
 

⇒$x=3000\times 7$  

⇒$x=21000$ 
 

Therefore, number of spectator is 21,000.