Hey there

Whenever these types of question comes just think of the base in this case base is 4.

Verification- just divide 16 by 4 and write each time the remainder just the way you convert any decimal number into binary you will find the answer as 100 so same way if you'll divide 56 by 4 and write the remainder each time you will get answer 320. Just keep in mind we write th remainder in reverse order like binary numbers conversions.

Good luck