Question

You need 150g of flour for 12 cakes, how much flour do you need for 30 cakes?

Answer 1

150g_______12cakes
xg_________30cakes
x=150*12/30=5*12=60 g

Answer 2

150 g flour for 12 cakes
x g flour for 30 cakes
x = (150 x 30) : 12 = 375 g of flour

another method:

150 flour for 12 cakes
??? for 30 cakes

30 : 12 = 2.5
150 x 2.5 = 375 g flour