Answer:
The Answer is 1111
Step-by-step explanation:
15 = 2(7)+1
7=2(3)+1
3=2(1)+1
1=2(0)+1
look the remainder of division by 2 : 1111 in binary system
verify : 15 = 1(2^0)+ 1(2^1)+ 1(2^2)+ 1(2^3 = 1+2+4+8=15 .....right