Answer
a) 25410
b) 8691
c) See Work Step by Step Part
Work Step by Step
a) 61502 = 6 * $8^{4}$ + 1* $8^{3}$ + 5* $8^{2}$ + + 0* $8^{1}$ + 2* $8^{0}$ = 24576 + 512 + 320 + 0 + 2 = 25410
So $61502_{8}$ = $25410_{10}$
b) 20763 = 2 * $8^{4}$ + 0 * $8^{3}$ + 7 * $8^{2}$ + 6 * $8^{1}$ + 3 * $8^{0}$ = 8192 + 0 + 448 + 48 + 3 = 8691
So $20763_{8}$ = $8691_{10}$
c) Let us convert $576_{8}$ to binary:
5 -> 101
7 -> 111
6 -> 110
So $576_{8}$ = $101111110_{2}$
Now let us convert $101110011_{2}$ to octal:
101 -> 5
110 -> 6
011 -> 3
So $101110011_{2}$ = $563_{8}$
