To evaluate the expression \(2.4x + 6.2y\) for \(x = 3.5\) and \(y = 1.8\), we substitute the values of \(x\) and \(y\) into the expression:
\[ 2.4(3.5) + 6.2(1.8) \]
Calculating \(2.4 \times 3.5\):
\[ 2.4 \times 3.5 = 8.4 \]
Now calculating \(6.2 \times 1.8\):
\[ 6.2 \times 1.8 = 11.16 \]
Now add the two results together:
\[ 8.4 + 11.16 = 19.56 \]
Thus, the value of the expression \(2.4x + 6.2y\) for \(x=3.5\) and \(y=1.8\) is:
\[ \boxed{19.56} \]
So the correct response is 19.56.