(a) Number-base conversions
(i) Convert \(125.625_{10}\) to base 2.
For the integer part, successive division by 2 gives:
Division Quotient Remainder 125 ÷ 2 62 1 62 ÷ 2 31 0 31 ÷ 2 15 1 15 ÷ 2 7 1 7 ÷ 2 3 1 3 ÷ 2 1 1 1 ÷ 2 0 1
Reading the remainders from bottom to top gives \(125_{10}=1111101_2\).
For the fractional part:
\(0.625\times2=1.25\), giving 1; \(0.25\times2=0.5\), giving 0; \(0.5\times2=1.0\), giving 1.
Therefore, \(0.625_{10}=0.101_2\), and hence
\[\boxed{125.625_{10}=1111101.101_2}\]
(ii) Convert \(111011.10011_2\) to base 8. Group the binary digits in threes from the binary point:
\[111\;011.100\;110_2=73.46_8\]
\[\boxed{111011.10011_2=73.46_8}\]
(b) \(X=11011011\), \(Y=11101101\), and \(Z=X\mathbin{\text{ AND }}Y\).
(i) Truth table for the AND operation
X Y Z = X AND Y 0 0 0 0 1 0 1 0 0 1 1 1
(ii) Logic-gate diagram
Two-input AND logic gate, where \(Z=X\text{ AND }Y\).
(iii) Value of \(Z\)
Bit position 1 2 3 4 5 6 7 8 X 1 1 0 1 1 0 1 1 Y 1 1 1 0 1 1 0 1 Z 1 1 0 0 1 0 0 1
\[\boxed{Z=11001001_2}\]