Payment on Plan A = $300
x is the number of hours Jake works.
Payment on Plan B = Fixed charges + (charge per hour) × (number of hours worked)
= $150 + $6.25(x)
= 150 + 6.25x
Since, the payment on Plan B should be more than Plan A,
150 + 6.25x > 300
6.25x > 300 - 150
6.25x > 150

x > 24
The minimum vale for x which satisfies this inequality is 25.
Hence, x = 25.
The statement "unit cubes with side lengths of 1/2 foot are added to fill the prism with no space remaining" is useless information so you can disregard that. All you need to know to calculate the volume is the length, width, and height.
Volume = length x width x height
Volume = (5/2) x 3 x 11/2
Volume = 15/2 x 11/2
Volume = 165/4
Volume = 41.25 ft cubed
The height is always measured perpendicular to the horizontal surface on which the pyramid rests, whereas the slant height is measured perpendicular to one edge of the base to the vertex, and, as we would say, appears to be slanted.
A)If the order of the speakers is important, we have 20x19x18x17, or 116,280 different options.
b) If order is not important, then we have 20 choose 4, or 4845 different slates. ☺☺☺☺