Answer
$1101000100000101$
Work Step by Step
The first 10 bits represents mantissa and the next 6 bits represent base-2 exponent.
$20.25=20+0.25=2^4+2^2+2^{-2}=10100.01_2=0.1010001\cdot 2^5$
The exponent is $5=101_2$
The number is:
$1101000100000101$
