Let \( x \) be the number of minutes that have passed.
The amount of liquid in the first vat, which starts empty and fills at a rate of 6 gallons per minute, can be expressed as: \[ 6x \]
The amount of liquid in the second vat, which starts with 10 gallons and fills at a rate of 4 gallons per minute, can be expressed as: \[ 10 + 4x \]
To find the time when both vats have an equal amount of liquid, we can set these two expressions equal to each other: \[ 6x = 10 + 4x \]
This equation can be solved to find \( x \). Thus, the equation showing when the two vats will have an equal amount of liquid is: \[ 6x = 10 + 4x \]