Numeric constant data type

Read our note on the data types of constants, the answer the following questions:

One of the following program snippets has a syntax error:

Dim tax, gross, net As Double
tax = 0.2 * gross

Dim tax, gross, net As Single
tax = 0.2 * gross

1. Which one has the syntax error?

2. How can you fix it?

(Be sure you have option strict on if you run a test).