Proportional Reasoning

One shopkeeper sells 3 pens for ₹30. Another sells 5 pens for ₹45. Sunita says the second shop is cheaper because you get more pens. Her brother says that is not how you compare. Who is right?

Two jugs of lemonade. The first has 2 spoons sugar in 4 glasses water; the second has 3 spoons sugar in 6 glasses water. Neha says the second is sweeter because it has more sugar. Is she right?

Kheer for 4 people needs 2 cups rice and 6 cups milk. Now it must be made for 8. Rohan says just add 2 more cups of milk (6+2=8), since the people only doubled from 4, so 2 extra is enough. Is Rohan's method right?

To make green, mix 3 spoons blue and 2 spoons yellow. Needing more, Sohan says make both 5 and 5, and the same green will come. Will making both equal give the same colour?

One tap fills a bucket in 10 minutes. Meera says two identical taps opened together will fill the same bucket in 20 minutes, because two taps means double the time. Is Meera right?