Question

the initial ratio of sugar to flour in a dough was to 2:7. To 9 kg of dough Jone added more sugar to make the sugar to flour ratio 2: 5. how much sugar did John letter added

Answer 1

2:7 to 2:5 let assume we had 2 kg sugar
and flour isn't changed so the ratio becomes
10:35 to 14:35
now we had 10+35 = 9 kg total, so 45=9, 1=1/5
so new amount of sugar is 14 = 14/5
and we had 10 = 10/5 amount of sugar

So sugar added is 14/5 - 10/5 = 4/5 = 0.800 gms of sugar