Question

A graph has quantity on the x-axis and price (dollars) on the y-axis. A supply line goes through (20, 30) and (30, 40). A demand line goes through (0, 10) and (30, 40).
The figure above shows a store’s supply-demand graph for coffee makers. If the store sells $375 worth of coffee makers, which of the following is a valid possible price for them?
a.
$15
b.
$25
c.
$40
d.
$55



Please select the best answer from the choices provided


A
B
C
D

Answer 1

B

Both lines have equation p = q + 10 (slope 1, y-intercept 10). If revenue p·q = 375, substitute q = p − 10:
p(p − 10) = 375 → p^2 − 10p − 375 = 0 → p = 25 (positive root).