
Yefim S. answered 01/14/20
Math Tutor with Experience
Volume v = x2z, where x is side of square base and z is hite. Then v't = v'x·x't + v'z·z't
v'x = 2xz, v'z = x2, Given: x = 10 ft, z = 12 ft, x't = 2 ft/sec, z't = - 2ft/sec.
Because rate of volume v't = 2xz·2 + x2·(-2) = 2·10·12·2 + 102·(-2) = 480 - 200 = 280 ft3/sec.
Answer is 4) v't = 280 ft3/sec