As the graph shows, the greatest x + y is the point at which the two lines intersect. Set the
equations of the two lines, y = x + 2 and y = 2x − 4, equal to each other and solve for x.
The resulting equation is x + 2 = 2x − 4. Solve for x to get – x + 2 = – 4 or – x = – 6, so
x = 4. Next, plug 4 into one of the two equations to solve for y. Therefore, y = 2(4) – 4 = 4
and x + y = 4 + 4 = 8. The correct answer is 8.
20. 72 The formula for the volume of a pyramid, given at the start of each math section, is V =
lwh, where l is the length of the base, w is the width of the base, and h is the height. Since
the cube has side 6, the length and width of the base are both 6. The height of the pyramid is
also the height of the cube, which is also 6. Plug these into the formula to get V = (6)(6)
(6) = 72.
Section 4: Math (Calculator)
