
Yefim S. answered 05/28/22
Math Tutor with Experience
Volume of water is v = (4 + 6)/2·4·h= 20h; dv/dt = 20dh/dt; dh/dt = (dv/dt)/20 = 2ft3/min/20ft2 = 0.1 ft/min

Les E.
asked 05/28/22The ends of a trough, 12 ft in length, are isosceles trapezoids with height 4 ft, upper base 6 ft and lower base 4 ft. Water is pumped into the trough at the rate of 2 ft^3/min. If the height of the water is 1 ft, how fast is the water level rising?
Yefim S. answered 05/28/22
Math Tutor with Experience
Volume of water is v = (4 + 6)/2·4·h= 20h; dv/dt = 20dh/dt; dh/dt = (dv/dt)/20 = 2ft3/min/20ft2 = 0.1 ft/min
Get a free answer to a quick problem.
Most questions answered within 4 hours.
Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.
Doug C.
Seems like question has not been interpreted correctly? 12 feet is the length of the trough which is a constant. h is the height of the water in the trough which is changing. At a given point in time one of the bases of the trapezoid cross section is 4, but the length of the other base depends on h. In fact the 2nd base will be 4 + 2(1/4)h (based on similar triangles). See: desmos.com/calculator/m62edog4b205/29/22