Your recipe calls for 1/2 a pound of potatoes. you use 1/6 of the bag of potatoes. whats the number of pounds per bag

I you use 1/6 of the bag for 1/2 a pound then you need to set up a proportion.

1/6 bag / 1 bag = 1/2 pound / x pounds      Cross Multiply
(1/6)*x = 1/2 pounds * 1 bag Divide by 1/6

Remember: in a 4 level fraction, the denominator inverts and multiplies.

x = 

3 pounds <<<< answer

The decimal expansion would be .27 repeated