If a/3 = b/8, then ( a + 3 ) : ( b + 8 ) is equal to?

Let a/3 = b/8 = K
Then, a = 3K, b = 8K
∴ (a + 3) / (b + 8) = (3K + 3) / (8K + 8)
= [3( K + 1)] / [8(K+1)] = 3/8
∴ ( a + 3 ) : (b + 8) = 3 : 8