Given :
Each morning a gardener uses 25 gallons of water from a barrel.
Each afternoon, she adds 15 gallons of water to the barrel.
To Find :
By how much has the volume of water in the barrel changed after 5 days.
Solution :
Amount of of water used from the barrel per day is :
A = 25 - 15 gallons
A = 10 gallons
Now, volume of water in the barrel changed after 5 days is :
V = A × 5 gallons
V = 10 × 5 gallons
V = 50 gallons
Therefore, volume of water in barrel is changed by 50 gallons.