Q23
Third pair (2.0, 6.8), eighth pair (8.4,2.3)
Line through both:
(8.4 - 2.0)(y - 6.8) = (2.3 - 6.8) (x - 2.0)
6.4(y - 6.8) = -4.5 (x - 2.0)
y = - (4.5/6.4) x + 9.0/6.4 + 6.8
y = - 0.703125 x
+ 8.20625
At x=9.8 that's y = - 0.703125 (9.8)
+ 8.20625 = 1.315625
Answer: Choice a
Q24.
They make $40 on leather, x, and $25 on canvas, y, so
f(x,y) = 40x + 25y
Answer: Choice a