WAEC Computer Studies 2022 Paper

Concept:Hexadecimal addition is the same as decimal addition, but each column carries when it reaches $16$, and $\mathrm{A}$ equals $10$.Explanation:Align the two numbers by place value and add from the rightmost column.Units column: $7_{16} + \mathrm{A}_{16} = 7 + 10 = 17_{10}$.Since $17_{10} = 11_{16}$, write $1$ in the units place and carry $1$ to the next column.Next column: $2_{16} + 0_{16} + 1_{16}$ (carry) $= 3_{16}$.Leftmost column: $1_{16} + 5_{16} = 6_{16}$.Thus, the sum is $631_{16}$.Answer:$\mathrm{127}_{16} + \mathrm{50A}_{16} = \mathrm{631}_{16}$Therefore, the correct option is C.