a) 40% - 12
100%-x
x=100*12/40=30
b) 40% - 20
100% - x
x=100*20/40=50
c) 30% - 24
100% - x
x=2400/30=80
d) 20% - 3
100% - x
x=300/20=15
e) 80% - 32
100% - x
x=3200/80=40
f) 70% - 140
100% - x
x=14000/70=200
g) 90% - 27
100% - x
x=2700/90=30
h) 15% - 24
100% - x
x=2400/15=160