Check Box Returns Value

Hello,

Need help! I am new to PDF forms and writing JavaScript.

I have a Checkbox that, when checked I want it to return "2 Weeks" in a Text Box (titled "Lead Time") and when unchecked it will return "8 Weeks" in the same Text Box.

Secondly, when that same Checkbox is checked, in another Text Box (titled "ExpediteCost"), a formula will take the Text Box titled "Cost"  and multiply by 10% and show the value in the "ExpediteCost" Text Box.  When the Checkbox is unchecked, the "ExpediteCost" Text Box will be blank or say "N/A".

Any help is greatly appreciated!