Question

Alberto has 15 gallons of water, during the first week 3/40 of the water evaporates, how much is left

Answer 1

15 gallons 37/40 13.875 left

Answer 2

If we know that 3/40 of the water evaporates, then 37/40 of the water is left.

We multiply this ratio by the original amount of water to get the remaining water.

15 gallons * 37/40 = 13.875 gallons left