The cuboid water tank with length, width and height of 50cm, 30cm and 60cm respectively is equipped with two water inlet pipes a and B. pipe a is opened first, and then the two pipes are opened together after a period of time 1. How many minutes later, tubes a and B will open at the same time? What's the depth of water? 2. How many milliliters of water can be injected into AB and ab pipes at the same time?

The cuboid water tank with length, width and height of 50cm, 30cm and 60cm respectively is equipped with two water inlet pipes a and B. pipe a is opened first, and then the two pipes are opened together after a period of time 1. How many minutes later, tubes a and B will open at the same time? What's the depth of water? 2. How many milliliters of water can be injected into AB and ab pipes at the same time?

1. It can be seen from the picture that tube a opened 15 minutes later, tube B also opened, so tube a and tube B opened at the same time 15 minutes later
At 15 minutes, the water depth is 10 cm
2. 15 minutes ago, pipe a was feeding water, so pipe a was feeding water 50 * 30 * 10 / 15 = 1000 ml per minute
The total speed is 50 * 30 * (50-10) / (25-10) = 4000 ml / min
So tube B water 4000-1000 per minute = 3000 ml