Answer
The required amount of salt is 1 U.S. teaspoon.
Work Step by Step
We can calculate the required amount of salt in British teaspoons:
$V = 1~saltspoon$
$V = 0.5~teaspoon$
Note that for dry measures, 1 British teaspoon = 2 U.S. teaspoons.
Therefore the required amount of salt is 1 U.S. teaspoon.
