The mean of five numbers is 30. If one number is excluded, then it becomes 28. The excluded number is

Sum of 5 numbers $=5\times 30=150$

One numbers $\left(x\right)$  is excluded Mean becomes 28

$\therefore$ Mean $=\frac{150-x}{4}=28$

$150-x=112$

$-x=112-150$

$-x=-38$

$x=38$

 $\therefore$ Excluded Number, $x=38$