You paid $4.76 total for 7 notebooks. To figure out how much each individual notebook cost, you divide the total cost by the number of things you bought, so
Cost of One Notebook = Total Cost of Notebooks / Number of Notebooks = $4.76 / 7 = $0.68
This is the unit rate.
To buy three notebooks, you just calculate the total cost of three notebooks at this price point, so
Cost of Three Notebooks = Cost of One Notebook * 3 Notebo0ks = $0.68 * 3 = $2.04
If there are 12 items adding up to 60%, we want to know how many items more it will take to equal 100% So set up this equation 12/x = .6 then solve for x. x=12/.6 x = 20 now that we know the total you can subtract 12 from 20 and get 8, that is the number of items left on the list.
