Respuesta :

taskmasters
You can solve it like this

2=milk (a); 1=milk (b)
9=tea (a); x= tea (b)

2:9=1:x (then multiply means and the extremes)
(means are 9 and 1; extremes are 2 and x)

9=2x
9/2= x
4.5 or 4 1/2=x

Therefore, using 1 litre of milk, we can have 4 1/2 tea.