2/5 of a rectangular container with a base area of 500 cm2 is filled with water. Another 1.75L of water is required to fill the tank to 3/4 of its capacity. What was the height of the water in the container at first?
1.75E3 cm^3 is .35 of capacity ... .75 - .40 = .35
1750 cm^3 / 500 cm^2 = 3.5 cm ... this is the depth change from 1.75 L
.40 / .35 = h / 3.5 cm