September price = S
October price = 1.2S = 1.5/1.2 = $1.25
Money earned in September = 0.4*900*450
Money earned in October = 0.4*700*420
0.30+1.50=1.80
The price was $1.80
b.More in September because they sold more
They earned $360 in September
They earned $280 in October
360-280=80
They earned $80 more in September than October