Two chemical plants are releasing waste into a holding tank. Plant 1 releases waste twice as fast as plant 2. Together they fill the tank in 4 hours. How long would it take the faster plant to fill the tank working alone?

6 hours.

Step-by-step explanation:

Let t represent time taken by plant 1 in hours to release the waste.

Part of waste released by plant 1 in one hour would be .  

We have been given that two chemical plant 1 releases waste twice as fast as plant 2, so time taken by plant 2 to release the waste would be .

Part of waste released by plant 2 in one hour would be .  

We are also told that together they fill the tank in 4 hours. So part of tank filled by both plants working together in one hour would be .

Therefore, it will take 6 hours for the faster plant to fill the tank working alone.

there is no question content here, but you for the free points! : d