Evaluate the expression for a=3, b=5, and c=10. (You will get a single number for your answer.)

Let's evaluate each expression step by step.

**Question 1: Evaluate the expression \(6a + 4b - 3c\) for \(a=3\), \(b=5\), and \(c=10\).**

Substituting the values into the expression:

\[
6(3) + 4(5) - 3(10)
\]

Calculating each term:

\[
6 \cdot 3 = 18
\]
\[
4 \cdot 5 = 20
\]
\[
3 \cdot 10 = 30
\]

Now combine the results:

\[
18 + 20 - 30 = 38 - 30 = 8
\]

So, the answer for Question 1 is:

\[
\boxed{8}
\]

---

**Question 2: Evaluate the expression \(2.4x + 6.2y\) for \(x=3.5\) and \(y=1.8\).**

Substituting the values into the expression:

\[
2.4(3.5) + 6.2(1.8)
\]

Calculating each term:

\[
2.4 \cdot 3.5 = 8.4
\]
\[
6.2 \cdot 1.8 = 11.16
\]

Now combine the results:

\[
8.4 + 11.16 = 19.56
\]

So, the answer for Question 2 is:

\[
\boxed{19.56}
\]