Separate the mantissa and exponent.

The given floating-point binary number is 11101011.
It is stored using 5 bits for the mantissa and 3 bits for the exponent.
Mantissa: $11101_2$
Exponent: $011_2$

The mantissa $11101_2$ is in 2's complement form. The binary point is assumed after the first bit (sign bit).
So, the mantissa is $1.1101_2$.
Since the MSB is 1, it's a negative number.
Value $= -1 \cdot 2^0 + 1 \cdot 2^{-1} + 1 \cdot 2^{-2} + 0 \cdot 2^{-3} + 1 \cdot 2^{-4}$
Value $= -1 + 0.5 + 0.25 + 0 + 0.0625 = -1 + 0.8125 = -0.1875_{10}$.

The exponent $011_2$ is in 2's complement form.