I’ve done these questions before and i’ve gotten confused because I have trouble with nagative numbers but i’ve gotten better st it. It’s -5
To know how many liters of water Bao use per liter of flour we have to divide the liters or flour so:

So Bao uses 0.33 or 1/3 of water per liter or flour
and to know hoy manu liters of flour Bao use per liter of water we have to made the oposite division so:

She use 3 liters of flour per liter of water
The answers are -3,5,13,21,29
Divide 60 by 12 and thats ur answer its 5...