Hallum
x = total # of square feet
T(cost) = 1.5x
if 700 sq. feet
T(cost) = 1.5(700) = $1050
Guillen, 10% less from Hallum per square foot
T(cost) = 1.5x - (1.5x * 0.1)
T(cost) = 1.5x - 0.15x
T(cost) = 1.35x
T(cost) = 1.35(700)
T(cost) = $945
answer
$945