Answer:
762
Step-by-step explanation:
Let,
abc is an unknown 3 digit number in that
a = hundredth digit
b = tenth digit
c = ones digit
Given,
a = 7
c + b = 8
b = a - 1
So we known,
a = 7 and b - 1 = a such that b = 7 - 1 which make b = 6
Since b = 6 and c + b = 8 then c + 6 = 8 which make c = 2
And the number is abc or 762