3a + b + c -------------- (1)
5b = a + c -------------- (2)
c = 80 + b -------------- (3)
put c = 80 + b in equation (2)
5b = a + b + 80
5b = b = a + 80 => 4b = a + 80
b = \( {a \over 4}\) + \( {80 \over 4}\) = \( {a \over 4}\) + 20
put b = \( {a \over 4}\) + 20 and c = 80 + b in Eq (1)
3a = \( {a \over 4}\) + 20 + 80 + \( {a \over 4}\) + 20
3a = \( {a \over 4}\) + \( {a \over 4}\) + (80 + 20 + 20)
3a = 2 * \( {a \over 4} \) + 120 => 3a - \( {2a \over 4}\) = 120
\( {12a - 2a \over 4}\) = 120 => \( {10a \over 4}\) = 120 => a = \( {120 * 4 \over 10}\) = 48
put a = 48 and c = 80 + b in equation (2)
we get 5b = 48 + 80 + b => 5b - b = 128
4b = 128 => b = \( {128 \over 4}\) = 32
pluf the value of b in equation (3) we get
c = 80 + 32 = 112
Now do a + b + c to find your answer
a = 48, b = 32, c = 112
80 a + b + c = 48 + 32 + 112
= 192
80 a + b + c = 192 (Ans)
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