Hey there! I'm happy to help!
Let's represent the number of days with x.
WAREHOUSE A
200-15x
WAREHOUSE B
80+25x
We want to find how many days it will take for the two warehouses to have the same amount of coal. Let's put these expressions into an equation to show that they are equal and see what x is.
200-15x=80+25x
We subtract 25x from both sides.
200-40x=80
We subtract 200 from both sides.
-40x=-120
We divide both sides by -40
x=3
Therefore, warehouse A and warehouse B will have the same amount of coal after 3 days.
Have a wonderful day! :D