Answer
1101100101
Work Step by Step
Replace each hexadecimal digit with its equivalent 4-digit binary form. Add zeroes to the front of the binary value if necessary to create a 4-digit number.
$3_{16}=3_{10}=2^1+2^0=11_2=0011_2$
$6_{16}=6_{10}=2^2+2^1=110_2=0110_2$
$5_{16}=5_{10}=2^2+2^0=101_2=0101_2$
The leading zeroes can be dropped from the first group of 4 when writing the final answer.
$\underbrace{\ \ \ 3\ \ \ }\ \underbrace{\ \ \ 6\ \ \ }\ \underbrace{\ \ \ 5\ \ \ }$
$0011\ \ 0110\ \ 0101$
