Can you please help me solve this problem by alligation?

Question

Zinc Paste (APF) has the following formula:
Zinc Oxide 25g
Starch 25g
White Soft Paraffin 50g

After 50g of the paste is mixed with a further 50g of soft white paraffin, how much zinc oxide must be added to the mixture to produce a product containing 25% zinc oxide

ok so the paste made up in the question is 100 grams and has 12.5% zinc oxide. you cant just add another 12.5 grams of zinc oxide because then its 25g out of 112.5g which isnt 25%

Answer 1

You need to add the same according to the formula. The 50g of the paste you mixed in is half the quantity but contains the same proportion of the ingredients. So by preparing a paste using the same formula, you are actually increasing the quantity of the product by 50% but the contents would be the same.

It is just the same as saying, you mixed 1 and a half tube of the paste. You increased the quantity but it contains the same ingredients.

(That's just based on my logical thinking though!)