tolong ya beserta rumus plissss

lb x b = lf x f
30 x 450 = 150 x f
13.500 = 150f
f = 13.500 : 150
f = 90

lb x b = lf x f
20 x 450 = 150 x f
9.000 = 150f
f = 9.000 : 150
f = 60

f1 - f2 = 90 - 60
= 30

C. dikurangi 30