B) Water flows at a steady rate from a tap.
It takes 40 seconds to fill a 4 litre watering can from the tap.
The rate at which water flows from the tap is halved.
Complete.
4 litres = cm3

I suppose that the result is 4000 cm^3 Because 1 liter = 1000 cubic centimeters. Therefore, 4 liters = 4* 1000 cubic centimeters = 4000 cm^3.

In Addition, there is another way to figure out, which is that 1 mL ( milliliters) is equivalent to 1 cubic centimeter. so, If there is 1,000 mL in a Liter then it’s possible to have 4,000 mL in 4 liters. Therefore, 4 liters = 4000 cm^3. Hope this helps.

If i think this is what your asking, he should look at the grams or pounds/ounces and compare the to their cost then max can identify which one is proportional and which is not ( i think xd)