78.75
(5 x 15) + (6 x 15) = 11 x 15 = 165
I cannot take this question seriously! The sum is 75.
75/(-5-10) = 75/(-15) = -5
75 - 100 + 0 = -25
-100
58 + 17 = 75
75
'Sum' is pretty much a synonym for add, and 5+5 or 5 plus 5 is 10.
75 + 5 = 80
31 Because, twice 31 is 62. And, 62 plus 13 is 75.
445