What happens to the reaction rate as the supply of toothpicks runs out?

For a reversible reaction:
At equilibrium, the rate of the forward reaction should be equal to the rate of the backwards reaction.

Increasing the amount of reactants would shift the equilibrium towards the formation of new products, so the rate of the forward reaction would increase until the equilibrium balance is reached again.
On the other hand, decreasing the amount of reactants would shift the equilibrium towards the formation of reactants, so the rate of the reverse reaction would increase until equilibrium is reached again.

Based on this, decreasing the supply of toothpicks (reactants) would shift the equilibrium towards the formation of reactants (towards the left) and the rate of the reverse reaction would increase until equilibrium is reached again.

So what you would do is go through and add 3 teaspoons(tsp) 6 times because of the 6 tablespoons(tbsp). which will give you an answer of 18. another way is to multiply 3x6=18.